Version original: Bahasa Inggris
Ini adalah ringkasan studi saya selama beberapa bulan dari web developer (otodidak, tanpa gelar sarjana informatika) hingga menjadi software engineer Google.
Saya telah mengupas catatan Google's Coaching Note dan berikut adalah hal-hal penting dari catatan tersebut. Ada beberapa poin yang saya tambahkan pada bagian akhir yang mungkin muncul dalam wawancara atau dapat berguna dalam proses penyelesaian masalah. Banyak poin berasal dari artikel Steve Yegge "Get that job at Google" yang berisi poin-poin dari Google's Coaching Note.
Saya sudah meringkas poin-poin penting menurut saran dari Yegge. Saya juga mengubah beberapa rekomendasinya berdasarkan informasi yang saya dapatkan dari kontak saya di Google. Pedoman ini ditujukan untuk software engineer baru dan mereka yang ingin beralih profesi dari web developer menjadi software engineer (dimana ilmu komputer diperlukan).
Jika Anda mengaku memiliki pengalaman bertahun-tahun dalam rekayasa perangkat lunak, bersiaplah untuk wawncara yang jauh lebih sulit. Baca lebih lanjut.
Jika Anda memiliki pengalaman sebagai developer software/web, catat bahwa Google memandang software engineer berbeda dari developer software/web karena software engineer menggunakan ilmu komputer.
Jika Anda ingin menjadi teknisi ketahanan sistem atau teknisi sistem, lebih banyak pelajari pada bagian tambahan (jaringan, keamanan).
- Apa ini?
- Mengapa menggunakan ini?
- Bagaimana cara menggunakannya
- Masuk ke Mode Googley
- Jangan merasa anda kurang pintar
- Tentang Google
- Tentang Sumber Video
- Proses Interview dan Preparasi Wawancara Secara Umum
- Pilih Satu Bahasa Pemrograman untuk Wawancara
- Daftar Buku
- Sebelum Anda Mulai
- Apa yang Tidak Akan Dibahas
- Ilmu Prasyarat
- Rencana Harian
- Kompleksitas Algoritma / Big-O / Analisis Asimptotik
- Struktur Data
- Pengetahauan Tambahan
- Trees
- Trees - Catatan & Latar Belakang
- Binary search trees: BSTs
- Heap / Priority Queue / Binary Heap
- balanced search trees (konsep dasar, tidak mendalam)
- traversals: preorder, inorder, postorder, BFS, DFS
- Sorting
- selection
- insertion
- heapsort
- quicksort
- merge sort
- Graphs
- directed
- undirected
- adjacency matrix
- adjacency list
- traversals: BFS, DFS
- Pengetahuan Tambahan Lainnya
- Perancangan Sistem, Skalabilitas, Penganganan Data (jika anda memiliki pengalaman 4 tahun lebih)
- Ulasan Akhir
- Latihan Pertanyaan Pemrograman
- Soal-soal Pemrograman
- Menjelang Proses Interview
- CV Anda
- Perkirakan Pertanyaan Yang Akan Diajukan
- Bertanyalah Pada Pewawancara
- Saat Anda Berhasil Mendapatkan Pekerjaannya
---------------- Semua dibawah ini bersifat opsional ----------------
- Buku Tambahan
- Materi Tambahan
- Pemrograman Dinamis
- Kompilator
- Bilangan Titik Mengambang
- Unicode
- Endianness
- Emacs and vi(m)
- Unix command line tools
- Teori Informasi
- Pariti & Kode Hamming
- Entropi
- Kriptografi
- Kompresi
- Jaringan (bersiaplah mendapatkan pertanyaan jaringan apabila anda ingin menjadi system engineer)
- Sekuritas Komputer
- Garbage collection
- Pemrograman Paralel
- Pengiriman Pesan, Serialisasi, dan Sistem Queueing
- Fast Fourier Transform
- Bloom Filter
- HyperLogLog
- Locality-Sensitive Hashing
- van Emde Boas Trees
- Augmented Data Structures
- Tries
- N-ary (K-ary, M-ary) trees
- Balanced search trees
- AVL trees
- Splay trees
- Red/black trees
- 2-3 search trees
- 2-3-4 Trees (aka 2-4 trees)
- N-ary (K-ary, M-ary) trees
- B-Trees
- k-D Trees
- Skip lists
- Network Flows
- Disjoint Sets & Union Find
- Matematika untuk Pemrosesan Cepat
- Treap
- Pemrograman Linear
- Geometri, Convex hull
- Matematika Diskrit
- Pembelajaran Mesin
- Go
- Detil Tambahan pada Beberapa Subjek
- Seri Video
- Kursus Ilmu Komputer
Saya mengikuti rencana ini untuk mempersiapkan saya dalam menghadapi wawancara kerja Google. Sejak 1997, saya telah menciptakan berbagai situs, servis, dan mendirikan startup. Saya memiliki gelar ekonomi, bukan gelar ilmu komputer. Saya telah meraih kesuksesan dalam karir saya, tapi saya ingin bekerja di Google. Saya ingin masuk ke sistem yang lebih besar dan mempunyai pemahaman mendalam tentang sistem komputer, efesiensi algoritma, performa struktur data, bahasa tingkat rendah, dan bagaimana semuanya bekerja. Jika anda tidak mengetahui satu pun, Google tidak akan mempekerjakan anda.
Ketika saya memulai proyek ini, saya tidak tahu tentang stack dari sebuah heap, tidak tahu tentang notasi Big-O apapun, begitupula dengan struktur data trees, atau bagaimana menyusuri sebuah graph. Jika saya harus menulis algoritma penyortiran, saya bisa katakan pada anda bahwa hasilnya tidak akan memuaskan. Setiap struktur data yang saya pernah pakai sudah tertanam dalam bahasa yang saya gunakan, dan saya tidak tahu bagaimana mereka bekerja secara riil. Saya tidak pernah diharuskan untuk mengatur penggunaan memori kecuali proses yang saya jalankan akan memberikan error 'memori tidak cukup', sehingga saya harus mencari jalan keluarnya. Saya pernah menggunakan beberapa array multidimensi dalam hidup saya dan ribuan array asosiatif, tapi saya tidak pernah menciptakan struktur data dari nol.
Tetapi setelah menjalani rencana studi ini saya memiliki kepercayaan diri yang tinggi bahwa saya akan diterima. Ini adalah rencana yang panjang. Ini akan menyita waktu saya selama berbulan-bulan. Tetapi jika anda sudah tidak asing lagi dengan materi yang dibutuhkan, hal ini akan membutuhkan waktu jauh lebih sedikit.
Apapun dibawah ini adalah garis besar, dan anda harus menguasai materi dari atas ke bawah secara runut.
Saya menggunakan markdown spesial dari Github, termasuk daftar tugas untuk mengecek perkembangan.
Buat branch baru sehingga anda bisa mencentang seperti ini, bubuhi tanda x dalam tanda kurung: [x]
Fork sebuah branch dan ikuti perintah berikut
git checkout -b progress
git remote add jwasham https://github.com/jwasham/google-interview-university
git fetch --all
Tandai semua kotak dengan tanda X setalah anda menyelesaikannya
git add .
git commit -m "Marked x"
git rebase jwasham/master
git push --force
Lebih jauh tentang markdown Github
Print satu atau beberapa foto dari "future Googler" (untuk ditempel tentunya) sebagai reminder anda apa hasil usaha yang anda akan dapatkan.
- Para engineers/programmer di google adalah orang-orang pintar, tapi banyak dari mereka berpikir bahwa mereka tidak cukup pintar, walaupun mereka bekerja di Google.
- Mitos dari programmer yang jenius
- Hal yang berbahaya untuk pergi sendirian: Bertarung dengan monster yang tidak kelihatan di dunia teknologi
- Untuk pelajar - Google Careers: Technical Development Guide
- Bagaimana Pencari Bekerja:
- Seri:
- Book: How Google Works
- Made by Google announcement - Oct 2016 (video)
Beberapa video hanya dapat diakses dengan mengikuti kelas di Coursera, Edx, atau Lynda.com. Beberapa link tersebut biasa disebut MOOC (massive open online course) atau belajar online, seperti layaknya anda berkuliah biasa namun bedanya ini online dan diikuti oleh banyak orang dari seluruh dunia. Terkadang suatu saat kelas yang ada tidak dapat diikuti untuk sementara, dan harus menunggu beberapa bulan. Karena kelas tersebut ada waktunya dalam pembelajaran, dan ada waktunya untuk mendaftar, layaknya anda berkuliah. Khusus untuk Lynda.com merupakan situs yang berbayar untuk mengakses materinya.
Selain saya membagikan ilmu kepada kalian semua, saya juga mengapresiasi bantuan anda untuk menambahkan sumber pembelajaran yang gratis dan selalu terbuka untuk umum, seperti video di youtube untuk sebagai selingan dari kuliah online dari website yang disebutkan diatas.
Saya suka menggunakan media pembelajaran berbasiskan universitas.
-
Video:
- How to Work at Google: Prepare for an Engineering Interview (video)
- How to Work at Google: Example Coding/Engineering Interview (video)
- How to Work at Google - Candidate Coaching Session (video)
- Google Recruiters Share Technical Interview Tips (video)
- How to Work at Google: Tech Resume Preparation (video)
-
Artikel:
- Becoming a Googler in Three Steps
- Get That Job at Google
- semua hal-hal yang dia sebutkan itu sudah terdaftar dibawah dan kamu harus tahu
- (very dated) How To Get A Job At Google, Interview Questions, Hiring Process
- Phone Screen Questions
-
Materi kelas untuk persiapan:
- Software Engineer Interview Unleashed (paid course):
- Learn how to make yourself ready for software engineer interviews from a former Google interviewer.
- Software Engineer Interview Unleashed (paid course):
-
Tambahan (tidak disarankan oleh Google tapi saya tambahkan sendiri):
- ABC: Always Be Coding
- Four Steps To Google Without A Degree
- Whiteboarding
- How Google Thinks About Hiring, Management And Culture
- Effective Whiteboarding during Programming Interviews
- Cracking The Coding Interview Set 1:
- How to Get a Job at the Big 4:
- Failing at Google Interviews
Saya menulis artikel pendek tentang topik hal tersebut: Penting:Pilih Satu Bahasa Pemrograman untuk wawancara dengan Google (Penting: Pilih Satu Bahasa Pemrograman untuk wawancara dengan Google)
Anda dapat menggunakan sebuah bahasa pemrograman yang nyaman bagi anda untuk melaksanakan salah satu bagian wawancara yaitu sesi mengkoding, tapi bagi Google, berikut adalah beberapa pilihan:
- C++
- Java
- Python
Anda juga dapat menggunakan beberapa bahasa pemrograman berikut, tapi cari informasi dahulu tentang hal ini, karena mungkin ada kualifikasi khusus:
- JavaScript
- Ruby
Anda harus sangat nyaman dan memahami bahasa yang akan digunakan untuk wawancara tersebut.
Baca lebih banyak tentang pilihan:
- http://www.byte-by-byte.com/choose-the-right-language-for-your-coding-interview/
- http://blog.codingforinterviews.com/best-programming-language-jobs/
- https://www.quora.com/What-is-the-best-language-to-program-in-for-an-in-person-Google-interview
Lihat beberapa sumber bahasa pemrograman disini
Anda akan melihat beberapa C, C++, dan Python di cantumkan di link dibawah, karena saya juga sedang belajar. Ada beberapa buku juga diikutkan dalam list dibawah ini, lihat bagian bawah.
Ini adalah daftar pendek yang saya gunakan. Ini disingkat untuk menghemat waktu Anda.
- Programming Interviews Exposed: Secrets to Landing Your Next Job, 2nd Edition
- jawaban di C++ and Java
- direkomendasikan di Google candidate coaching
- ini adalah pemanasan yang baik untuk Cracking the Coding Interview
- tidak terlalu sulit, kebanyakan masalah mungkin lebih mudah daripada apa yang akan anda lihat dalam sebuah wawancara (dari apa yang saya baca)
- Cracking the Coding Interview, 6th Edition
- jawaban in Java
- direkomendasikan di the Google Careers site
- Jika kamu melihat orang-orang mereferensikan "The Google Resume", itu adalah sebuah buku yang diganti oleh "Cracking the Coding Interview".
Jika anda memiliki banyak waktu:
- Elements of Programming Interviews
- semua kode adalah di C++, sangat bagus jika anda menggunakan C++ di wawancara anda.
- sebuah buku yang bagus mengenai pemecahan masalah secara umum.
Jika kekurangan waktu:
- Write Great Code: Volume 1: Understanding the Machine
- Buku ini dirilis pada tahun 2004, dan agak ketinggalan jaman, tetapi dengan sumber daya yang hebat bisa untuk memahami komputer secara singkat.
- Penulis menemukan HLA, sehingga menyebutkan dan memberi contoh di HLA dengan sebutir garam. Tidak banyak digunakan, tapi contoh yang baik seperti apa assembly itu.
- Bab-bab ini patut dibaca untuk memberikan dasar yang baik:
- Chapter 2 - Numeric Representation
- Chapter 3 - Binary Arithmetic and Bit Operations
- Chapter 4 - Floating-Point Representation
- Chapter 5 - Character Representation
- Chapter 6 - Memory Organization and Access
- Chapter 7 - Composite Data Types and Memory Objects
- Chapter 9 - CPU Architecture
- Chapter 10 - Instruction Set Architecture
- Chapter 11 - Memory Architecture and Organization
Jika anda punya banyak waktu (Saya ingin buku ini):
- Computer Architecture, Fifth Edition: A Quantitative Approach
- Untuk orang kaya, lebih up-to-date (2011), tapi dengan pemeliharaan jangka panjang
Anda harus memilih sebuah bahasa pemgrograman untuk wawancara (lihat diatas). Berikut adalah rekomendasi bahasa dari saya. Saya tidak memiliki sumber daya untuk semua bahasa. Saya menyambut penambahan.
Jika meskipun anda membaca salah satu dari ini, anda harus memiliki semua pengetahuan struktur data dan algoritma, anda harus mulai melakukan pemecahan masalah koding. Anda dapat melewati semua video ceramah di proyek ini, kecuali jika anda ingin sebuah review.
Additional language-specific resources here.
Saya belum membaca keduanya. tapi mereka dinilai sangat bagus dan ditulis oleh Sedgewick. Dia mengagumkan.
- Algorithms in C++, Parts 1-4: Fundamentals, Data Structure, Sorting, Searching
- Algorithms in C++ Part 5: Graph Algorithms
Jika anda memiliki rekomendasi yang lebih baik untuk C++, tolong beritahu saya. Mencari sumber daya yang komprehensif.
- Algorithms (Sedgewick and Wayne)
- video dengan buku (dan Sedgewick!):
OR:
- Data Structures and Algorithms in Java
- oleh Goodrich, Tamassia, Goldwasser
- digunakan sebagai teks opsional untuk kursus pengenalan CS di UC Berkeley
- lihat laporan buku saya pada versi Python dibawah. Buku ini mencakup topik-topik yang sama.
- Data Structures and Algorithms in Python
- oleh Goodrich, Tamassia, Goldwasser
- Saya mencintai buku ini. Mencakup segala hal dan lainnya.
- kode Pythonic
- laporan buku saya: https://googleyasheck.com/book-report-data-structures-and-algorithms-in-python/
Beberapa orang merekomendasikan ini, tapi saya pikir itu akan berlebihan, kecuali jika anda punya pengalaman di software engineering bertahun-tahun dan mengharapkan sebuah wawancara yang jauh lebih sulit
-
Algorithm Design Manual (Skiena)
- Sebagai sebuah review dan pengenalan masalah
- Bagian katalog algoritma adalah luar lingkup yang baik saat anda mendapatkan kesulitan di wawancara
- Buku ini mempunyai 2 bagian:
- class textbook on data structures and algorithms
- pros:
- adalah sebuah review yang bagus sebagai buku algoritma
- cerita bagus dari pengalamannya memecahkan masalah dalam industri dan akademisi
- contoh kode di C
- cons:
- dapat secara penuh dan tak tertembus sebagai CLRS, dan dalam beberapa kasus, CLRS mungkin menjadi alternatif yang lebih baik untuk beberapa mata pelajaran
- bab 7, 8, 9 bisa menyakitkan untuk mencoba mengikutinya, karena beberapa item yang tidak dijelaskan dengan baik atau membutuhkan kinerja otak yang lebih daripada yang saya miliki
- jangan salah paham: Saya suka Skiena, gaya mengajarnya, dan kelakuannya, tapi aku mungkin tidak akan seperti bahan Stony Brook.
- pros:
- algorithm catalog:
- ini adalah alasan nyata kamu membeli buku ini
- tentang untuk mendapatkan bagian ini. Akan diperbarui disini suatu waktu setelah saya membuat jalan melewati itu.
- class textbook on data structures and algorithms
- Mengutip Yegge: "More than any other book it helped me understand just how astonishingly commonplace (and important) graph problems are – they should be part of every working programmer's toolkit. The book also covers basic data structures and sorting algorithms, which is a nice bonus. But the gold mine is the second half of the book, which is a sort of encyclopedia of 1-pagers on zillions of useful problems and various ways to solve them, without too much detail. Almost every 1-pager has a simple picture, making it easy to remember. This is a great way to learn how to identify hundreds of problem types."
- Dapat menyewa di kindle
- Half.com adalah sumber daya yang besar untuk buku dengan harga yang baik.
- Jawaban:
- Errata
-
- Penting: Membaca buku ini hanya akan memiliki nilai yang terbatas. Buku ini adalah review besar algoritma dan struktur data, tetapi akan mengajarkan cara menulis kode yang baik. Anda harus dapat mengkode yang layak secara efisien.
- Mengutip Yegge: "But if you want to come into your interviews prepped, then consider deferring your application until you've made your way through that book."
- Half.com adalah sumber daya yang besar untuk buku dengan harga yang baik.
- aka CLR, terkadang CLRS, karena Stein terlambat untuk permainan.
-
- Pasangan pertama dari bab yang menyajikan solusi cerdas untuk masalah pemrogramman (beberapa sangat tua saat menggunakan tipe data) tapi itu hanya sebuah intro. Ini sebuah buku panduan tentang program desain dan arsitektur, seperti Code Complete, tapi jauh lebih pendek.
-
"Algorithms and Programming: Problems and Solutions" oleh Shen- Sebuah buku yang baik, tapi setelah bekerja melalui masalah pada halaman, saya frustasi dengan Pascal, do while loops, 1-indexed arrays, dan hasil post-condition yang tidak jelas.
- Lebih suka menghabiskan waktu di masalah coding dari buku lain atau masalah coding online.
Daftar ini tumbuh selama berbulan-bulan, dan ya, itu jenis keluaran dari tangan.
Berikut adalah beberapa kesalahan yang saya buat sehingga anda akan memiliki pengalaman yang lebih baik.
Saya menonton video berjam-jam dan mengambil catatan yang berlebihan, dan beberapa bulan kemudian disana ada banyak yang tidak saya ingat. Saya menghabiskan 3 hari melalui catatan saya dan membuat flashcards sehingga saya bisa meninjaunya dengan lebih cepat.
Tolong baca sehingga anda tidak akan membuat kesalahan seperti saya:
Menguasai Pengetahuan Ilmu Komputer
Untuk mengatasi masalah tersebut, saya membuat situs flashcards kecil di mana saya bisa menambahkan flashcards dari 2 jenis: umum dan code. Setiap kartu memiliki format yang berbeda.
Saya membuat sebuah mobile-first website jadi saya bisa mereview di telepon dan tablet saya, dimanapun saya berada.
Membuat punya anda sendiri secara gratis:
- Repo website flashcards
- Database flashcards saya (lama - 1200 kartu):
- Database flashcards saya (baru - 1800 kartu):
Perlu diingat aku pergi keluar kapal dan memiliki kartu meliputi segala sesuatu dari bahasa assembly dan Python trivia untuk pembelajaran machine learning dan statistik. Ini terlalu banyak untuk apa yang diminta oleh Google.
Catatan di flashcards: Pertama kali anda mengenali dan anda tahu jawabannya, jangan menandainya sebagai dikenal. Anda harus melihat kartu yang sama dan menjawab beberapa kali dengan benar sebelum anda benar-benar tahu akan hal itu. Pengulangan akan membuat pengetahuan yang lebih di otak anda.
Sebuah alternatif untuk menggunakan situs flashcards saya adalah Anki, yang telah direkomendasikan kepada saya berkali-kali. Ini menggunakan sistem pengulangan untuk membantu anda mengingatnya. Ini user-friendly, yang tersedia di semua platform dan memiliki sebuah sistem cloud sync. Ini memerlukan biaya $25 di iOS tapi ini gratis di platform lainnya.
Database flashcard saya di format Anki: https://ankiweb.net/shared/info/25173560 (terimakasih @xiewenya)
Aku menyimpan satu set cheat sheet pada ASCII, OSI stack, Big-O notasi, dan banyak lagi. Saya mempelajari mereka ketika saya memiliki beberapa waktu luang.
Mengambil istirahat dari masalah pemgrogramman selama setengah jam dan pergi melalui flashcards anda.
Disana ada banyak gangguan yang dapat menyita waktu yang berharga. Fokus dan kosentrasi adalah hal yang sulit.
Daftar besar ini semua dimulai sebagai daftar to-do pribadi yang dibuat dari catatan Google interview coaching. Ini adalah teknologi lazim mereka tetapi tidak disebutkan dalam catatan itu:
- SQL
- Javascript
- HTML, CSS, dan teknologi front-end lainnya
Beberapa mata pelajaran mengambil satu hari, dan beberapa akan mengambil beberapa hari. Beberapa hanya belajar dan tidak ada yang diimplimentasikan.
Setiap hari saya mengambil satu subjek dari daftar di bawah ini, menonton video tentang subjek itu, dan menulis sebuah implementasi di:
- C - menggunakan structs dan functions yang mengambil sebuah struct * dan sesuatu yang lain seperti args.
- C++ - tanpa menggunakan built-in types
- C++ - menggunakan built-in types, seperti STL's std::list untuk daftar link
- Python - menggunakan built-in types (untuk terus berlatih Python)
- dan menulis tes untuk memastikan saya melakukannya dengan benar, kadang-kadang hanya menggunakan assert() statements yang sederhana
- Anda mungkin bisa menggunakan Java atau sesuatu yang lain, ini hanyalah pendapat saya.
Anda tidak perlu semua ini. Anda hanya perlu satu bahasa untuk wawancara.
Mengapa meng-kode di semua ini?
- Latihan, latihan, latihan, sampai saya sakit karenanya, dan dapat melakukannya tanpa masalah (beberapa memiliki banyak kasus dan rincian pembukuan untuk diingat)
- Bekerja dalam batasan baku (mengalokasikan/membebaskan memori tanpa bantuan dari sekumpulan sampah (kecuali Python))
- Menggunakan built-in types jadi saya memiliki pengalaman menggunakan alat built-in untuk digunakan di dunia nyata (tidak akan menulis daftar pelaksanaan saya sendiri di produksi)
Saya mungkin tidak punya waktu untuk melakukan semua ini untuk setiap mata pelajaran, tapi saya akan mencobanya.
Anda dapat melihat kode saya di sini:
- [C] (https://github.com/jwasham/practice-c)
- [C++] (https://github.com/jwasham/practice-cpp)
- [Python] (https://github.com/jwasham/practice-python)
Anda tidak perlu susah payah menghafal setiap algoritma.
Menulis kode pada papan tulis atau kertas, bukan komputer. Uji dengan beberapa sampel masukan. Kemudian menguji itu pada komputer.
-
Belajar C
- C ada dimana-mana. Anda akan melihat contoh di buku, perkuliahan, video, dimanapun ketika kamu belajar.
- C Programming Language, Vol 2
- Ini adalah sebuah buku yang pendek, tapi itu akan memberikanmu sebuah pegangan yang kuat di bahasa C dan Anda akan melakukan latihan kecil dengan secara singkat dan cakap. Memahami C akan membantu anda memahami bagaimana program dan memori itu bekerja.
- answers to questions
-
Bagaimana komputer memproses sebuah program:
-
tidak ada untuk dilaksanakan
-
Big O Notation (and Omega and Theta) - best mathematical explanation (video)
-
Skiena:
-
TopCoder (includes recurrence relations and master theorem):
-
Jika beberapa ceramah terlalu membingunkan, anda dapat melompatinya kebawah dan tonton the discrete mathematics videos untuk mendapatkan latar belakang pengetahuan.
-
- Implement an automatically resizing vector.
- Description:
- Implement a vector (mutable array with automatic resizing):
- Practice coding using arrays and pointers, and pointer math to jump to an index instead of using indexing.
- new raw data array with allocated memory
- can allocate int array under the hood, just not use its features
- start with 16, or if starting number is greater, use power of 2 - 16, 32, 64, 128
- size() - number of items
- capacity() - number of items it can hold
- is_empty()
- at(index) - returns item at given index, blows up if index out of bounds
- push(item)
- insert(index, item) - inserts item at index, shifts that index's value and trailing elements to the right
- prepend(item) - can use insert above at index 0
- pop() - remove from end, return value
- delete(index) - delete item at index, shifting all trailing elements left
- remove(item) - looks for value and removes index holding it (even if in multiple places)
- find(item) - looks for value and returns first index with that value, -1 if not found
- resize(new_capacity) // private function
- when you reach capacity, resize to double the size
- when popping an item, if size is 1/4 of capacity, resize to half
- Time
- O(1) to add/remove at end (amortized for allocations for more space), index, or update
- O(n) to insert/remove elsewhere
- Space
- contiguous in memory, so proximity helps performance
- space needed = (array capacity, which is >= n) * size of item, but even if 2n, still O(n)
-
- Description:
- C Code (video) - not the whole video, just portions about Node struct and memory allocation.
- Linked List vs Arrays:
- why you should avoid linked lists (video)
- Gotcha: you need pointer to pointer knowledge: (for when you pass a pointer to a function that may change the address where that pointer points) This page is just to get a grasp on ptr to ptr. I don't recommend this list traversal style. Readability and maintainability suffer due to cleverness.
- implement (I did with tail pointer & without):
- size() - returns number of data elements in list
- empty() - bool returns true if empty
- value_at(index) - returns the value of the nth item (starting at 0 for first)
- push_front(value) - adds an item to the front of the list
- pop_front() - remove front item and return its value
- push_back(value) - adds an item at the end
- pop_back() - removes end item and returns its value
- front() - get value of front item
- back() - get value of end item
- insert(index, value) - insert value at index, so current item at that index is pointed to by new item at index
- erase(index) - removes node at given index
- value_n_from_end(n) - returns the value of the node at nth position from the end of the list
- reverse() - reverses the list
- remove_value(value) - removes the first item in the list with this value
- Doubly-linked List
- Description (video)
- No need to implement
-
- Stacks (video)
- Using Stacks Last-In First-Out (video)
- Will not implement. Implementing with array is trivial.
-
- Using Queues First-In First-Out(video)
- Queue (video)
- Circular buffer/FIFO
- Priority Queues (video)
- Implement using linked-list, with tail pointer:
- enqueue(value) - adds value at position at tail
- dequeue() - returns value and removes least recently added element (front)
- empty()
- Implement using fixed-sized array:
- enqueue(value) - adds item at end of available storage
- dequeue() - returns value and removes least recently added element
- empty()
- full()
- Cost:
- a bad implementation using linked list where you enqueue at head and dequeue at tail would be O(n) because you'd need the next to last element, causing a full traversal each dequeue
- enqueue: O(1) (amortized, linked list and array [probing])
- dequeue: O(1) (linked list and array)
- empty: O(1) (linked list and array)
-
-
Videos:
-
Online Courses:
-
implement with array using linear probing
- hash(k, m) - m is size of hash table
- add(key, value) - if key already exists, update value
- exists(key)
- get(key)
- remove(key)
-
-
- Binary Search (video)
- Binary Search (video)
- detail
- Implement:
- binary search (on sorted array of integers)
- binary search using recursion
-
- Bits cheat sheet - you should know many of the powers of 2 from (2^1 to 2^16 and 2^32)
- Get a really good understanding of manipulating bits with: &, |, ^, ~, >>, <<
- 2s and 1s complement
- count set bits
- round to next power of 2:
- swap values:
- absolute value:
-
- Series: Core Trees (video)
- Series: Trees (video)
- basic tree construction
- traversal
- manipulation algorithms
- BFS (breadth-first search)
- MIT (video)
- level order (BFS, using queue) time complexity: O(n) space complexity: best: O(1), worst: O(n/2)=O(n)
- DFS (depth-first search)
- MIT (video)
- notes: time complexity: O(n) space complexity: best: O(log n) - avg. height of tree worst: O(n)
- inorder (DFS: left, self, right)
- postorder (DFS: left, right, self)
- preorder (DFS: self, left, right)
-
- Binary Search Tree Review (video)
- Series (video)
- starts with symbol table and goes through BST applications
- Introduction (video)
- MIT (video)
- C/C++:
- Binary search tree - Implementation in C/C++ (video)
- BST implementation - memory allocation in stack and heap (video)
- Find min and max element in a binary search tree (video)
- Find height of a binary tree (video)
- Binary tree traversal - breadth-first and depth-first strategies (video)
- Binary tree: Level Order Traversal (video)
- Binary tree traversal: Preorder, Inorder, Postorder (video)
- Check if a binary tree is binary search tree or not (video)
- Delete a node from Binary Search Tree (video)
- Inorder Successor in a binary search tree (video)
- Implement:
- insert // insert value into tree
- get_node_count // get count of values stored
- print_values // prints the values in the tree, from min to max
- delete_tree
- is_in_tree // returns true if given value exists in the tree
- get_height // returns the height in nodes (single node's height is 1)
- get_min // returns the minimum value stored in the tree
- get_max // returns the maximum value stored in the tree
- is_binary_search_tree
- delete_value
- get_successor // returns next-highest value in tree after given value, -1 if none
-
- visualized as a tree, but is usually linear in storage (array, linked list)
- Heap
- Introduction (video)
- Naive Implementations (video)
- Binary Trees (video)
- Tree Height Remark (video)
- Basic Operations (video)
- Complete Binary Trees (video)
- Pseudocode (video)
- Heap Sort - jumps to start (video)
- Heap Sort (video)
- Building a heap (video)
- MIT: Heaps and Heap Sort (video)
- CS 61B Lecture 24: Priority Queues (video)
- Linear Time BuildHeap (max-heap)
- Implement a max-heap:
- insert
- sift_up - needed for insert
- get_max - returns the max item, without removing it
- get_size() - return number of elements stored
- is_empty() - returns true if heap contains no elements
- extract_max - returns the max item, removing it
- sift_down - needed for extract_max
- remove(i) - removes item at index x
- heapify - create a heap from an array of elements, needed for heap_sort
- heap_sort() - take an unsorted array and turn it into a sorted array in-place using a max heap
- note: using a min heap instead would save operations, but double the space needed (cannot do in-place).
-
Notes:
- Implement sorts & know best case/worst case, average complexity of each:
- no bubble sort - it's terrible - O(n^2), except when n <= 16
- stability in sorting algorithms ("Is Quicksort stable?")
- Which algorithms can be used on linked lists? Which on arrays? Which on both?
- I wouldn't recommend sorting a linked list, but merge sort is doable.
- Merge Sort For Linked List
- Implement sorts & know best case/worst case, average complexity of each:
-
For heapsort, see Heap data structure above. Heap sort is great, but not stable.
-
UC Berkeley:
-
Merge sort code:
-
Quick sort code:
-
Implement:
- Mergesort: O(n log n) average and worst case
- Quicksort O(n log n) average case
- Selection sort and insertion sort are both O(n^2) average and worst case
- For heapsort, see Heap data structure above.
-
Not required, but I recommended them:
If you need more detail on this subject, see "Sorting" section in Additional Detail on Some Subjects
Graphs can be used to represent many problems in computer science, so this section is long, like trees and sorting were.
-
Notes from Yegge:
- There are three basic ways to represent a graph in memory:
- objects and pointers
- matrix
- adjacency list
- Familiarize yourself with each representation and its pros & cons
- BFS and DFS - know their computational complexity, their tradeoffs, and how to implement them in real code
- When asked a question, look for a graph-based solution first, then move on if none.
- There are three basic ways to represent a graph in memory:
-
Skiena Lectures - great intro:
- CSE373 2012 - Lecture 11 - Graph Data Structures (video)
- CSE373 2012 - Lecture 12 - Breadth-First Search (video)
- CSE373 2012 - Lecture 13 - Graph Algorithms (video)
- CSE373 2012 - Lecture 14 - Graph Algorithms (con't) (video)
- CSE373 2012 - Lecture 15 - Graph Algorithms (con't 2) (video)
- CSE373 2012 - Lecture 16 - Graph Algorithms (con't 3) (video)
-
Graphs (review and more):
- 6.006 Single-Source Shortest Paths Problem (video)
- 6.006 Dijkstra (video)
- 6.006 Bellman-Ford (video)
- 6.006 Speeding Up Dijkstra (video)
- Aduni: Graph Algorithms I - Topological Sorting, Minimum Spanning Trees, Prim's Algorithm - Lecture 6 (video)
- Aduni: Graph Algorithms II - DFS, BFS, Kruskal's Algorithm, Union Find Data Structure - Lecture 7 (video)
- Aduni: Graph Algorithms III: Shortest Path - Lecture 8 (video)
- Aduni: Graph Alg. IV: Intro to geometric algorithms - Lecture 9 (video)
- CS 61B 2014 (starting at 58:09) (video)
- CS 61B 2014: Weighted graphs (video)
- Greedy Algorithms: Minimum Spanning Tree (video)
- Strongly Connected Components Kosaraju's Algorithm Graph Algorithm (video)
-
Full Coursera Course:
-
Yegge: If you get a chance, try to study up on fancier algorithms:
- Dijkstra's algorithm - see above - 6.006
- A*
-
I'll implement:
- DFS with adjacency list (recursive)
- DFS with adjacency list (iterative with stack)
- DFS with adjacency matrix (recursive)
- DFS with adjacency matrix (iterative with stack)
- BFS with adjacency list
- BFS with adjacency matrix
- single-source shortest path (Dijkstra)
- minimum spanning tree
- DFS-based algorithms (see Aduni videos above):
- check for cycle (needed for topological sort, since we'll check for cycle before starting)
- topological sort
- count connected components in a graph
- list strongly connected components
- check for bipartite graph
You'll get more graph practice in Skiena's book (see Books section below) and the interview books
-
- Stanford lectures on recursion & backtracking:
- when it is appropriate to use it
- how is tail recursion better than not?
-
- Optional: UML 2.0 Series (video)
- Object-Oriented Software Engineering: Software Dev Using UML and Java (21 videos):
- Can skip this if you have a great grasp of OO and OO design practices.
- OOSE: Software Dev Using UML and Java
- SOLID OOP Principles:
- Bob Martin SOLID Principles of Object Oriented and Agile Design (video)
- SOLID Design Patterns in C# (video)
- SOLID Principles (video)
- S - Single Responsibility Principle | Single responsibility to each Object
- O - Open/Closed Principal | On production level Objects are ready for extension for not for modification
- L - Liskov Substitution Principal | Base Class and Derived class follow ‘IS A’ principal
- I - Interface segregation principle | clients should not be forced to implement interfaces they don't use
- D -Dependency Inversion principle | Reduce the dependency In composition of objects.
-
- Quick UML review (video)
- Learn these patterns:
- strategy
- singleton
- adapter
- prototype
- decorator
- visitor
- factory, abstract factory
- facade
- observer
- proxy
- delegate
- command
- state
- memento
- iterator
- composite
- flyweight
- Chapter 6 (Part 1) - Patterns (video)
- Chapter 6 (Part 2) - Abstraction-Occurrence, General Hierarchy, Player-Role, Singleton, Observer, Delegation (video)
- Chapter 6 (Part 3) - Adapter, Facade, Immutable, Read-Only Interface, Proxy (video)
- Series of videos (27 videos)
- Head First Design Patterns
- I know the canonical book is "Design Patterns: Elements of Reusable Object-Oriented Software", but Head First is great for beginners to OO.
- Handy reference: 101 Design Patterns & Tips for Developers
-
- Math Skills: How to find Factorial, Permutation and Combination (Choose) (video)
- Make School: Probability (video)
- Make School: More Probability and Markov Chains (video)
- Khan Academy:
- Course layout:
- Just the videos - 41 (each are simple and each are short):
-
- Know about the most famous classes of NP-complete problems, such as traveling salesman and the knapsack problem, and be able to recognize them when an interviewer asks you them in disguise.
- Know what NP-complete means.
- Computational Complexity (video)
- Simonson:
- Skiena:
- Complexity: P, NP, NP-completeness, Reductions (video)
- Complexity: Approximation Algorithms (video)
- Complexity: Fixed-Parameter Algorithms (video)
- Peter Norvig discusses near-optimal solutions to traveling salesman problem:
- Pages 1048 - 1140 in CLRS if you have it.
-
- Computer Science 162 - Operating Systems (25 videos):
- for processes and threads see videos 1-11
- Operating Systems and System Programming (video)
- What Is The Difference Between A Process And A Thread?
- Covers:
- Processes, Threads, Concurrency issues
- difference between processes and threads
- processes
- threads
- locks
- mutexes
- semaphores
- monitors
- how they work
- deadlock
- livelock
- CPU activity, interrupts, context switching
- Modern concurrency constructs with multicore processors
- Process resource needs (memory: code, static storage, stack, heap, and also file descriptors, i/o)
- Thread resource needs (shares above (minus stack) with other threads in the same process but each has its own pc, stack counter, registers, and stack)
- Forking is really copy on write (read-only) until the new process writes to memory, then it does a full copy.
- Context switching
- How context switching is initiated by the operating system and underlying hardware
- Processes, Threads, Concurrency issues
- threads in C++ (series - 10 videos)
- concurrency in Python (videos):
- Computer Science 162 - Operating Systems (25 videos):
-
- These are Google papers and well-known papers.
- Reading all from end to end with full comprehension will likely take more time than you have. I recommend being selective on papers and their sections.
- 1978: Communicating Sequential Processes
- 2003: The Google File System
- replaced by Colossus in 2012
- 2004: MapReduce: Simplified Data Processing on Large Clusters
- mostly replaced by Cloud Dataflow?
- 2006: Bigtable: A Distributed Storage System for Structured Data
- 2006: The Chubby Lock Service for Loosely-Coupled Distributed Systems
- 2007: What Every Programmer Should Know About Memory (very long, and the author encourages skipping of some sections)
- 2010: Dapper, a Large-Scale Distributed Systems Tracing Infrastructure
- 2010: Dremel: Interactive Analysis of Web-Scale Datasets
- 2012: Google's Colossus
- paper not available
- 2012: AddressSanitizer: A Fast Address Sanity Checker:
- 2013: Spanner: Google’s Globally-Distributed Database:
- 2014: Machine Learning: The High-Interest Credit Card of Technical Debt
- 2015: Continuous Pipelines at Google
- 2015: High-Availability at Massive Scale: Building Google’s Data Infrastructure for Ads
- 2015: TensorFlow: Large-Scale Machine Learning on Heterogeneous Distributed Systems
- 2015: How Developers Search for Code: A Case Study
- 2016: Borg, Omega, and Kubernetes
-
- To cover:
- how unit testing works
- what are mock objects
- what is integration testing
- what is dependency injection
- Agile Software Testing with James Bach (video)
- Open Lecture by James Bach on Software Testing (video)
- Steve Freeman - Test-Driven Development (that’s not what we meant) (video)
- TDD is dead. Long live testing.
- Is TDD dead? (video)
- Video series (152 videos) - not all are needed (video)
- Test-Driven Web Development with Python
- Dependency injection:
- How to write tests
- To cover:
-
- in an OS, how it works
- can be gleaned from Operating System videos
-
- understand what lies beneath the programming APIs you use
- can you implement them?
-
- Sedgewick - Suffix Arrays (video)
- Sedgewick - Substring Search (videos)
- Search pattern in text (video)
If you need more detail on this subject, see "String Matching" section in Additional Detail on Some Subjects
- You can expect system design questions if you have 4+ years of experience.
- Scalability and System Design are very large topics with many topics and resources, since there is a lot to consider when designing a software/hardware system that can scale. Expect to spend quite a bit of time on this.
- Considerations from Yegge:
- scalability
- Distill large data sets to single values
- Transform one data set to another
- Handling obscenely large amounts of data
- system design
- features sets
- interfaces
- class hierarchies
- designing a system under certain constraints
- simplicity and robustness
- tradeoffs
- performance analysis and optimization
- scalability
- START HERE: System Design from HiredInTech
- How Do I Prepare To Answer Design Questions In A Technical Inverview?
- 8 Things You Need to Know Before a System Design Interview
- Algorithm design
- Database Normalization - 1NF, 2NF, 3NF and 4NF (video)
- System Design Interview - There are a lot of resources in this one. Look through the articles and examples. I put some of them below.
- How to ace a systems design interview
- Numbers Everyone Should Know
- How long does it take to make a context switch?
- Transactions Across Datacenters (video)
- A plain English introduction to CAP Theorem
- Paxos Consensus algorithm:
- Consistent Hashing
- NoSQL Patterns
- Scalability:
- Great overview (video)
- Short series:
- Scalable Web Architecture and Distributed Systems
- Fallacies of Distributed Computing Explained
- Pragmatic Programming Techniques
- Jeff Dean - Building Software Systems At Google and Lessons Learned (video)
- Introduction to Architecting Systems for Scale
- Scaling mobile games to a global audience using App Engine and Cloud Datastore (video)
- How Google Does Planet-Scale Engineering for Planet-Scale Infra (video)
- The Importance of Algorithms
- Sharding
- Scale at Facebook (2009)
- Scale at Facebook (2012), "Building for a Billion Users" (video)
- Engineering for the Long Game - Astrid Atkinson Keynote(video)
- 7 Years Of YouTube Scalability Lessons In 30 Minutes
- How PayPal Scaled To Billions Of Transactions Daily Using Just 8VMs
- How to Remove Duplicates in Large Datasets
- A look inside Etsy's scale and engineering culture with Jon Cowie (video)
- What Led Amazon to its Own Microservices Architecture
- To Compress Or Not To Compress, That Was Uber's Question
- Asyncio Tarantool Queue, Get In The Queue
- When Should Approximate Query Processing Be Used?
- Google's Transition From Single Datacenter, To Failover, To A Native Multihomed Architecture
- Spanner
- Egnyte Architecture: Lessons Learned In Building And Scaling A Multi Petabyte Distributed System
- Machine Learning Driven Programming: A New Programming For A New World
- The Image Optimization Technology That Serves Millions Of Requests Per Day
- A Patreon Architecture Short
- Tinder: How Does One Of The Largest Recommendation Engines Decide Who You'll See Next?
- Design Of A Modern Cache
- Live Video Streaming At Facebook Scale
- A Beginner's Guide To Scaling To 11 Million+ Users On Amazon's AWS
- How Does The Use Of Docker Effect Latency?
- Does AMP Counter An Existential Threat To Google?
- A 360 Degree View Of The Entire Netflix Stack
- Latency Is Everywhere And It Costs You Sales - How To Crush It
- Serverless (very long, just need the gist)
- What Powers Instagram: Hundreds of Instances, Dozens of Technologies
- Cinchcast Architecture - Producing 1,500 Hours Of Audio Every Day
- Justin.Tv's Live Video Broadcasting Architecture
- Playfish's Social Gaming Architecture - 50 Million Monthly Users And Growing
- TripAdvisor Architecture - 40M Visitors, 200M Dynamic Page Views, 30TB Data
- PlentyOfFish Architecture
- Salesforce Architecture - How They Handle 1.3 Billion Transactions A Day
- ESPN's Architecture At Scale - Operating At 100,000 Duh Nuh Nuhs Per Second
- See "Messaging, Serialization, and Queueing Systems" way below for info on some of the technologies that can glue services together
- Twitter:
- For even more, see "Mining Massive Datasets" video series in the Video Series section.
- Practicing the system design process: Here are some ideas to try working through on paper, each with some documentation on how it was handled in the real world:
- review: System Design from HiredInTech
- cheat sheet
- flow:
- Understand the problem and scope:
- define the use cases, with interviewer's help
- suggest additional features
- remove items that interviewer deems out of scope
- assume high availability is required, add as a use case
- Think about constraints:
- ask how many requests per month
- ask how many requests per second (they may volunteer it or make you do the math)
- estimate reads vs. writes percentage
- keep 80/20 rule in mind when estimating
- how much data written per second
- total storage required over 5 years
- how much data read per second
- Abstract design:
- layers (service, data, caching)
- infrastructure: load balancing, messaging
- rough overview of any key algorithm that drives the service
- consider bottlenecks and determine solutions
- Understand the problem and scope:
- Exercises:
This section will have shorter videos that can you watch pretty quickly to review most of the important concepts.
It's nice if you want a refresher often.
- Series of 2-3 minutes short subject videos (23 videos)
- Series of 2-5 minutes short subject videos - Michael Sambol (18 videos):
- Sedgewick Videos - Algorithms I
- Sedgewick Videos - Algorithms II
Now that you know all the computer science topics above, it's time to practice answering coding problems.
Coding question practice is not about memorizing answers to programming problems.
Why you need to practice doing programming problems:
- problem recognition, and where the right data structures and algorithms fit in
- gathering requirements for the problem
- talking your way through the problem like you will in the interview
- coding on a whiteboard or paper, not a computer
- coming up with time and space complexity for your solutions
- testing your solutions
There is a great intro for methodical, communicative problem solving in an interview. You'll get this from the programming interview books, too, but I found this outstanding: Algorithm design canvas
My Process for Coding Interview (Book) Exercises
No whiteboard at home? That makes sense. I'm a weirdo and have a big whiteboard. Instead of a whiteboard, pick up a large drawing pad from an art store. You can sit on the couch and practice. This is my "sofa whiteboard". I added the pen in the photo for scale. If you use a pen, you'll wish you could erase. Gets messy quick.
Supplemental:
- Mathematics for Topcoders
- Dynamic Programming – From Novice to Advanced
- MIT Interview Materials
- Exercises for getting better at a given language
Read and Do Programming Problems (in this order):
- Programming Interviews Exposed: Secrets to Landing Your Next Job, 2nd Edition
- answers in C, C++ and Java
- Cracking the Coding Interview, 6th Edition
- answers in Java
See Book List above
Once you've learned your brains out, put those brains to work. Take coding challenges every day, as many as you can.
Challenge sites:
- LeetCode
- TopCoder
- Project Euler (math-focused)
- Codewars
- HackerRank
- Codility
- InterviewCake
- Geeks for Geeks
- InterviewBit
Maybe:
- Cracking The Coding Interview Set 2 (videos):
- Ten Tips for a (Slightly) Less Awful Resume
- See Resume prep items in Cracking The Coding Interview and back of Programming Interviews Exposed
Think of about 20 interview questions you'll get, along with the lines of the items below. Have 2-3 answers for each. Have a story, not just data, about something you accomplished.
- Why do you want this job?
- What's a tough problem you've solved?
- Biggest challenges faced?
- Best/worst designs seen?
- Ideas for improving an existing Google product.
- How do you work best, as an individual and as part of a team?
- Which of your skills or experiences would be assets in the role and why?
- What did you most enjoy at [job x / project y]?
- What was the biggest challenge you faced at [job x / project y]?
- What was the hardest bug you faced at [job x / project y]?
- What did you learn at [job x / project y]?
- What would you have done better at [job x / project y]?
Some of mine (I already may know answer to but want their opinion or team perspective):
- How large is your team?
- What does your dev cycle look like? Do you do waterfall/sprints/agile?
- Are rushes to deadlines common? Or is there flexibility?
- How are decisions made in your team?
- How many meetings do you have per week?
- Do you feel your work environment helps you concentrate?
- What are you working on?
- What do you like about it?
- What is the work life like?
Congratulations!
Keep learning.
You're never really done.
*****************************************************************************************************
*****************************************************************************************************
Everything below this point is optional. These are my recommendations, not Google's.
By studying these, you'll get greater exposure to more CS concepts, and will be better prepared for
any software engineering job. You'll be a much more well-rounded software engineer.
*****************************************************************************************************
*****************************************************************************************************
- The Unix Programming Environment
- an oldie but a goodie
- The Linux Command Line: A Complete Introduction
- a modern option
- TCP/IP Illustrated Series
- Head First Design Patterns
- a gentle introduction to design patterns
- Design Patterns: Elements of Reusable Object-Oriented Software
- aka the "Gang Of Four" book, or GOF
- the canonical design patterns book
- Site Reliability Engineering
- UNIX and Linux System Administration Handbook, 4th Edition
-
- This subject can be pretty difficult, as each DP soluble problem must be defined as a recursion relation, and coming up with it can be tricky.
- I suggest looking at many examples of DP problems until you have a solid understanding of the pattern involved.
- Videos:
- the Skiena videos can be hard to follow since he sometimes uses the whiteboard, which is too small to see
- Skiena: CSE373 2012 - Lecture 19 - Introduction to Dynamic Programming (video)
- Skiena: CSE373 2012 - Lecture 20 - Edit Distance (video)
- Skiena: CSE373 2012 - Lecture 21 - Dynamic Programming Examples (video)
- Skiena: CSE373 2012 - Lecture 22 - Applications of Dynamic Programming (video)
- Simonson: Dynamic Programming 0 (starts at 59:18) (video)
- Simonson: Dynamic Programming I - Lecture 11 (video)
- Simonson: Dynamic programming II - Lecture 12 (video)
- List of individual DP problems (each is short): Dynamic Programming (video)
- Yale Lecture notes:
- Coursera:
-
- Big And Little Endian
- Big Endian Vs Little Endian (video)
- Big And Little Endian Inside/Out (video)
- Very technical talk for kernel devs. Don't worry if most is over your head.
- The first half is enough.
-
- suggested by Yegge, from an old Amazon recruiting post: Familiarize yourself with a unix-based code editor
- vi(m):
- emacs:
-
- Khan Academy
- more about Markov processes:
- See more in MIT 6.050J Information and Entropy series below.
-
- Intro
- Parity
- Hamming Code:
- Error Checking
-
- also see videos below
- make sure to watch information theory videos first
- Information Theory, Claude Shannon, Entropy, Redundancy, Data Compression & Bits (video)
-
- also see videos below
- make sure to watch information theory videos first
- Khan Academy Series
- Cryptography: Hash Functions
- Cryptography: Encryption
-
- make sure to watch information theory videos first
- Computerphile (videos):
- Compressor Head videos
- (optional) Google Developers Live: GZIP is not enough!
-
- if you have networking experience or want to be a systems engineer, expect questions
- otherwise, this is just good to know
- Khan Academy
- UDP and TCP: Comparison of Transport Protocols
- TCP/IP and the OSI Model Explained!
- Packet Transmission across the Internet. Networking & TCP/IP tutorial.
- HTTP
- SSL and HTTPS
- SSL/TLS
- HTTP 2.0
- Video Series (21 videos)
- Subnetting Demystified - Part 5 CIDR Notation
-
- Given a Bloom filter with m bits and k hashing functions, both insertion and membership testing are O(k)
- Bloom Filters
- Bloom Filters | Mining of Massive Datasets | Stanford University
- Tutorial
- How To Write A Bloom Filter App
-
- used to determine the similarity of documents
- the opposite of MD5 or SHA which are used to determine if 2 documents/strings are exactly the same.
- Simhashing (hopefully) made simple
-
- Note there are different kinds of tries. Some have prefixes, some don't, and some use string instead of bits to track the path.
- I read through code, but will not implement.
- Sedgewick - Tries (3 videos)
- Notes on Data Structures and Programming Techniques
- Short course videos:
- The Trie: A Neglected Data Structure
- TopCoder - Using Tries
- Stanford Lecture (real world use case) (video)
- MIT, Advanced Data Structures, Strings (can get pretty obscure about halfway through)
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Know least one type of balanced binary tree (and know how it's implemented):
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"Among balanced search trees, AVL and 2/3 trees are now passé, and red-black trees seem to be more popular. A particularly interesting self-organizing data structure is the splay tree, which uses rotations to move any accessed key to the root." - Skiena
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Of these, I chose to implement a splay tree. From what I've read, you won't implement a balanced search tree in your interview. But I wanted exposure to coding one up and let's face it, splay trees are the bee's knees. I did read a lot of red-black tree code.
- splay tree: insert, search, delete functions If you end up implementing red/black tree try just these:
- search and insertion functions, skipping delete
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I want to learn more about B-Tree since it's used so widely with very large data sets.
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AVL trees
- In practice: From what I can tell, these aren't used much in practice, but I could see where they would be: The AVL tree is another structure supporting O(log n) search, insertion, and removal. It is more rigidly balanced than red–black trees, leading to slower insertion and removal but faster retrieval. This makes it attractive for data structures that may be built once and loaded without reconstruction, such as language dictionaries (or program dictionaries, such as the opcodes of an assembler or interpreter).
- MIT AVL Trees / AVL Sort (video)
- AVL Trees (video)
- AVL Tree Implementation (video)
- Split And Merge
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Splay trees
- In practice: Splay trees are typically used in the implementation of caches, memory allocators, routers, garbage collectors, data compression, ropes (replacement of string used for long text strings), in Windows NT (in the virtual memory, networking and file system code) etc.
- CS 61B: Splay Trees (video)
- MIT Lecture: Splay Trees:
- Gets very mathy, but watch the last 10 minutes for sure.
- Video
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Red/black trees
- these are a translation of a 2-3 tree (see below)
- In practice: Red–black trees offer worst-case guarantees for insertion time, deletion time, and search time. Not only does this make them valuable in time-sensitive applications such as real-time applications, but it makes them valuable building blocks in other data structures which provide worst-case guarantees; for example, many data structures used in computational geometry can be based on red–black trees, and the Completely Fair Scheduler used in current Linux kernels uses red–black trees. In the version 8 of Java, the Collection HashMap has been modified such that instead of using a LinkedList to store identical elements with poor hashcodes, a Red-Black tree is used.
- Aduni - Algorithms - Lecture 4 (link jumps to starting point) (video)
- Aduni - Algorithms - Lecture 5 (video)
- Black Tree
- An Introduction To Binary Search And Red Black Tree
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2-3 search trees
- In practice: 2-3 trees have faster inserts at the expense of slower searches (since height is more compared to AVL trees).
- You would use 2-3 tree very rarely because its implementation involves different types of nodes. Instead, people use Red Black trees.
- 23-Tree Intuition and Definition (video)
- Binary View of 23-Tree
- 2-3 Trees (student recitation) (video)
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2-3-4 Trees (aka 2-4 trees)
- In practice: For every 2-4 tree, there are corresponding red–black trees with data elements in the same order. The insertion and deletion operations on 2-4 trees are also equivalent to color-flipping and rotations in red–black trees. This makes 2-4 trees an important tool for understanding the logic behind red–black trees, and this is why many introductory algorithm texts introduce 2-4 trees just before red–black trees, even though 2-4 trees are not often used in practice.
- CS 61B Lecture 26: Balanced Search Trees (video)
- Bottom Up 234-Trees (video)
- Top Down 234-Trees (video)
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N-ary (K-ary, M-ary) trees
- note: the N or K is the branching factor (max branches)
- binary trees are a 2-ary tree, with branching factor = 2
- 2-3 trees are 3-ary
- K-Ary Tree
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B-Trees
- fun fact: it's a mystery, but the B could stand for Boeing, Balanced, or Bayer (co-inventor)
- In Practice: B-Trees are widely used in databases. Most modern filesystems use B-trees (or Variants). In addition to its use in databases, the B-tree is also used in filesystems to allow quick random access to an arbitrary block in a particular file. The basic problem is turning the file block i address into a disk block (or perhaps to a cylinder-head-sector) address.
- B-Tree
- Introduction to B-Trees (video)
- B-Tree Definition and Insertion (video)
- B-Tree Deletion (video)
- MIT 6.851 - Memory Hierarchy Models (video) - covers cache-oblivious B-Trees, very interesting data structures - the first 37 minutes are very technical, may be skipped (B is block size, cache line size)
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- great for finding number of points in a rectangle or higher dimension object
- a good fit for k-nearest neighbors
- Kd Trees (video)
- kNN K-d tree algorithm (video)
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- "These are somewhat of a cult data structure" - Skiena
- Randomization: Skip Lists (video)
- For animations and a little more detail
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- Combination of a binary search tree and a heap
- Treap
- Data Structures: Treaps explained (video)
- Applications in set operations
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- see videos below
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- Why ML?
- Google's Cloud Machine learning tools (video)
- Google Developers' Machine Learning Recipes (Scikit Learn & Tensorflow) (video)
- Tensorflow (video)
- Tensorflow Tutorials
- Practical Guide to implementing Neural Networks in Python (using Theano)
- Courses:
- Great starter course: Machine Learning - videos only - see videos 12-18 for a review of linear algebra (14 and 15 are duplicates)
- Neural Networks for Machine Learning
- Google's Deep Learning Nanodegree
- Google/Kaggle Machine Learning Engineer Nanodegree
- Self-Driving Car Engineer Nanodegree
- Metis Online Course ($99 for 2 months)
- Resources:
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I added these to reinforce some ideas already presented above, but didn't want to include them
above because it's just too much. It's easy to overdo it on a subject.
You want to get hired in this century, right?
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Union-Find
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More Dynamic Programming (videos)
- 6.006: Dynamic Programming I: Fibonacci, Shortest Paths
- 6.006: Dynamic Programming II: Text Justification, Blackjack
- 6.006: DP III: Parenthesization, Edit Distance, Knapsack
- 6.006: DP IV: Guitar Fingering, Tetris, Super Mario Bros.
- 6.046: Dynamic Programming & Advanced DP
- 6.046: Dynamic Programming: All-Pairs Shortest Paths
- 6.046: Dynamic Programming (student recitation)
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Advanced Graph Processing (videos)
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MIT Probability (mathy, and go slowly, which is good for mathy things) (videos):
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String Matching
- Rabin-Karp (videos):
- Knuth-Morris-Pratt (KMP):
- Boyer–Moore string search algorithm
- Coursera: Algorithms on Strings
- starts off great, but by the time it gets past KMP it gets more complicated than it needs to be
- nice explanation of tries
- can be skipped
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Sorting
- Stanford lectures on sorting:
- Shai Simonson, Aduni.org:
- Steven Skiena lectures on sorting:
Sit back and enjoy. "Netflix and skill" :P
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List of individual Dynamic Programming problems (each is short)
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Excellent - MIT Calculus Revisited: Single Variable Calculus
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Computer Science 70, 001 - Spring 2015 - Discrete Mathematics and Probability Theory
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CSE373 - Analysis of Algorithms (25 videos)
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UC Berkeley CS 152: Computer Architecture and Engineering (20 videos)
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Carnegie Mellon - Computer Architecture Lectures (39 videos)
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MIT 6.042J: Mathematics for Computer Science, Fall 2010 (25 videos)
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MIT 6.050J: Information and Entropy, Spring 2008 (19 videos)