problems.org

Problems

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Codeforces

Problem List 1000 –> 1250

1. [ ] 1747C Swap Gamegames
2. [ ] 1766B Notepad#implementation
3. [ ] 1820B JoJo’s Incredible Adventuresmath, strings, two pointers
4. [ ] 1822D Super-Permutationconstructive algorithms, math
5. [ ] 1826B Lunatic Never Content math, number theory
6. [ ] 1843D Apple Treecombinatorics, dfs and similar, dp, math, trees
7. [ ] 1846D Rudolph and Christmas Treeconstructive algorithms, geometry, math
8. [ ] 1850E Cardboard for Picturesbinary search, geometry, implementation, math
9. [ ] 1858C Yet Another Permutation Problemconstructive algorithms, math, number theory
10. [X] 1732A Bestiebrute force, combinatorics, constructive algorithms, implementation, math, number theory
11. [X] 1734C Removing Smallest Multiplesgreedy, math
12. [X] 1743C Save the Magazinesconstructive algorithms, dp, greedy
13. [X] 1744C Traffic Lightbinary search, implementation, two pointers
14. [X] 1760E Binary Inversionsdata structures, greedy, math
15. [X] 1765M Minimum LCMmath, number theory
16. [X] 1783B Matrix of Differencesconstructive algorithms, math
17. [X] 1725B Basketball Togetherbinary search, greedy, sortings
18. [X] 1726B Mainak and Interesting Sequencebitmasks, constructive algorithms, math
19. [X] 1729D Friends and the Restaurantgreedy, sortings, two pointers
20. [X] 1729C Jumping on Tilesconstructive algorithms, strings
21. [X] 1730C Minimum Notationdata structures, greedy, math, sortings
22. [X] 1731B Kill Demodogsgreedy, math
23. [X] 1738B Prefix Sum Addictsconstructive algorithms, greedy, math, sortings
24. [X] 1739B Array Recoveryconstructive algorithms, greedy, math
25. [X] 1736B Playing with GCDmath, number theory
26. [X] 1741C Minimize the Thicknessbrute force, greedy, math, two pointers
27. [X] 1742E Scuzabinary search, greedy, math
28. [X] 1742D Coprimebrute force, greedy, number theory
29. [X] 1744D Divisibility by 2^ngreedy, math, sortings
30. [X] 1760D Challenging Valleysimplementation, two pointers
31. [X] 1761B Elimination of a Ringconstructive algorithms, greedy, implementation
32. [X] 1762B Make Array Goodconstructive algorithms, implementation, number theory, sortings
33. [X] 1763B Incineratebinary search, brute force, data structures, implementation, math, sortings
34. [X] 1765E Exchangebrute force, math
35. [X] 1770B Koxia and Permutationconstructive algorithms
36. [X] 1770A Koxia and Whiteboardsbrute force, greedy
37. [X] 1772C Different Differencesconstructive algorithms, greedy, math
38. [X] 1780B GCD Partitionbrute force, greedy, math, number theory
39. [X] 1781B Going to the Cinemabrute force, greedy, sortings
40. [X] 1784A Monsters (easy version)brute force, greedy
41. [X] 1787B Number Factorizationgreedy, math, number theory
42. [X] 1788B Sum of Two Numbersconstructive algorithms, greedy, implementation, math, probabilities
43. [X] 1790D Matryoshkasdata structures, greedy, sortings
44. [X] 1790C Premutationbrute force, implementation, math
45. [X] 1791G1 Teleporters (Easy Version)greedy, sortings
46. [X] 1791E Negatives and Positivesdp, greedy, sortings
47. [X] 1791D Distinct Splitbrute force, greedy, strings
48. [X] 1792B Stand-up Comediangreedy, math
49. [X] 1793C Dora and Searchconstructive algorithms, data structures, two pointers
50. [X] 1793B Fedya and Arrayconstructive algorithms, math
51. [X] 1796B Asterisk-Minor Templateimplementation, strings
52. [X] 1797B Li Hua and Patternconstructive algorithms, greedy
53. [X] 1798B Three Sevensbrute force, data structures, greedy, implementation
54. [X] 1799B Equalize by Dividebrute force, constructive algorithms, greedy, math
55. [X] 1800D Remove Two Lettersdata structures, greedy, hashing, strings
56. [X] 1800C2 Powering the Hero (hard version)data structures, greedy
57. [X] 1800C1 Powering the Hero (easy version)data structures, greedy
58. [X] 1800B Count the Number of Pairsgreedy, strings
59. [X] 1808B Playing in a Casinomath, sortings
60. [X] 1811B Conveyor Beltsimplementation, math
61. [X] 1816B Grid Reconstructionconstructive algorithms, greedy
62. [X] 1826A Trust Nobodybrute force, greedy, implementation, sortings
63. [X] 1827A Counting Orderscombinatorics, math, sortings, two pointers
64. [X] 1829E The Lakesdfs and similar, dsu, graphs, implementation
65. [X] 1829D Gold Rushbrute force, dfs and similar, dp, implementation
66. [X] 1831B Array mergingconstructive algorithms, greedy
67. [X] 1832C Contrast Valuegreedy, implementation
68. [X] 1832B Maximum Sumbrute force, sortings, two pointers
69. [X] 1838B Minimize Permutation Subarraysconstructive algorithms, math
70. [X] 1839B Lampsgreedy, sortings
71. [X] 1840C Ski Resortcombinatorics, math, two pointers
72. [X] 1840B Binary Cafebitmasks, combinatorics, math
73. [X] 1841B Keep it Beautifulimplementation
74. [X] 1842B Tenzing and Booksbitmasks, greedy, math
75. [X] 1844B Permutations & Primesconstructive algorithms, math
76. [X] 1848B Vika and the Bridgebinary search, data structures, greedy, implementation, math, sortings
77. [X] 1849B Monstersgreedy, math, sortings
78. [X] 1851C Tiles Comebackgreedy
79. [X] 1853B Fibonaccharsisbinary search, brute force, math
80. [X] 1857C Assembly via Minimumsgreedy, sortings
81. [X] 1857B Maximum Roundinggreedy, implementation, math

Problem List 1300

Remaining

1. [X] 1829F Forever Winter dfs and similar, graphs, math
2. [ ] 1807E Interview binary search, implementation, interactive
3. [X] 1786B Cake Assembly Line brute force, sortings
4. [X] 1776H Beppa and SwerChat two pointers
5. [X] 1741D Masha and a Beautiful Tree dfs and similar, divide and conquer, graphs, sortings, trees
6. [X] 1736C1 Good Subarrays (Easy Version) binary search, data structures, schedules, two pointers
7. [ ] 1711B Party brute force, graphs
8. [X] 1698C 3SUM Closure brute force, data structures
9. [ ] 1675D Vertical Paths graphs, implementation, trees
10. [ ] 1556B Take Your Places! implementation
11. [ ] 1555B Two Tables brute force
12. [ ] 1493B Planet Lapituletti brute force, implementation
13. [ ] 1433E Two Round Dances combinatorics, math
14. [ ] 1424G Years data structures, sortings
15. [ ] 1373C Pluses and Minuses math
16. [ ] 1366B Shuffle math, two pointers
17. [ ] 1360D Buying Shovels math, number theory
18. [ ] 1352D Alice, Bob and Candies implementation
19. [X] 1839C Insert Zero and Invert Prefixconstructive algorithms
20. [X] 1850F We Were Both Childrenbrute force, implementation, math, number theory
21. [X] 1846E1 Rudolf and Snowflakes (simple version)brute force, implementation, math
22. [X] 1826C Dreaming of Freedomgreedy, math, number theory
23. [X] 1823C Strongly Compositegreedy, math, number theory
24. [X] 1821C Tear It Apartbrute force, implementation, math, strings
25. [X] 1819A Constructive Problembrute force, greedy
26. [X] 1857D Strong Verticesmath, sortings, trees
27. [X] 1851D Prefix Permutation Sumsimplementation, math
28. [X] 1844C Particlesdp, greedy, implementation, math

math

1. [X] 1815A Ian and Array Sorting greedy, math
2. [X] 1794C Scoring Subsequences binary search, greedy, math, two pointers
3. [X] 1788C Matching Numbers constructive algorithms, greedy, math
4. [X] 1778B The Forbidden Permutation greedy, math
5. [X] 1737B Ela’s Fitness and the Luxury Number binary search, implementation, math
6. [X] 1746C Permutation Operations constructive algorithms, greedy, implementation, math
7. [X] 1650D Twist the Permutation brute force, constructive algorithms, implementation, math
8. [X] 1459B Move and Turn dp, math
9. [X] 1618D Array and Operations dp, greedy, math
10. [X] 1669H Maximal AND bitmasks, greedy, math
11. [X] 1667A Make it Increasing brute force, greedy, math
12. [X] 1692F 3SUM brute force, math
13. [X] 1617C Paprika and Permutation binary search, greedy, math, sortings
14. [X] 1615B And It’s Non-Zero bitmasks, greedy, math
15. [X] 1612C Chat Ban binary search, math
16. [X] 1607D Blue-Red Permutation greedy, math, sortings
17. [X] 1601A Array Elimination bitmasks, greedy, math, number theory
18. [X] 1603A Di-visible Confusion constructive algorithms, math, number theory
19. [X] 1521B Nastia and a Good Array constructive algorithms, math, number theory
20. [X] 1594E1 Rubik’s Cube Coloring (easy version) combinatorics, math
21. [ ] 1571B Epic Novel*special problem, math
22. [X] 1560D Make a Power of Two greedy, math, strings
23. [X] 1538C Number of Pairs binary search, data structures, math, two pointers
24. [ ] 1558A Charmed by the Game brute force, math

graph

1. [ ] 1638C Inversion Graph data structures, dsu, graphs, math
2. [ ] 1534C Little Alawn’s Puzzle combinatorics, dp, dsu, graphs, math

constructive algorithms

1. [X] 1775B Gardener and the Array bitmasks, constructive algorithms
2. [ ] 1774C Ice and Fire constructive algorithms, dp, greedy
3. [X] 1768C Elemental Decompress constructive algorithms, greedy, implementation, sortings
4. [X] 1753A1 Make Nonzero Sum (easy version) constructive algorithms, dp, greedy
5. [X] 1733C Parity Shuffle Sorting constructive algorithms, sortings
6. [X] 1659B Bit Flipping bitmasks, constructive algorithms, greedy, strings
7. [X] 1647C Madoka and Childish Pranks constructive algorithms, greedy
8. [X] 1555C Coin Rows brute force, constructive algorithms, dp, implementation
9. [X] 1547D Co-growing Sequence bitmasks, constructive algorithms, greedy
10. [X] 1454D Number into Sequence constructive algorithms, math, number theory
11. [X] 1446A Knapsack constructive algorithms, greedy, sortings
12. [X] 1425H Huge Boxes of Animal Toys constructive algorithms
13. [X] 1420C1 Pokémon Army (easy version) constructive algorithms, dp, greedy
14. [X] 1401C Mere Array constructive algorithms, math, number theory, sortings
15. [X] 1381A1 Prefix Flip (Easy Version) constructive algorithms, data structures, strings
16. [X] 1367C Social Distance constructive algorithms, greedy, math
17. [X] 1365B Trouble Sort constructive algorithms, implementation

dp

1. [ ] 1769C2 Подкрутка II *special problem, dp
2. [X] 1766C Hamiltonian Wall dp, implementation
3. [X] 1703F Yet Another Problem About Pairs Satisfying an Inequality binary search, data structures, dp, greedy, sortings
4. [X] 1676G White-Black Balanced Subtrees dfs and similar, dp, graphs, trees
5. [X] 1661B Getting Zero bitmasks, brute force, dfs and similar, dp, graphs, greedy, shortest paths
6. [X] 1660C Get an Even String dp, greedy, strings
7. [ ] 1553B Reverse String brute force, dp, hashing, implementation, strings
8. [X] 1470A Strange Birthday Party binary search, dp, greedy, sortings, two pointers
9. [X] 1466C Canine poetry dp, greedy, strings
10. [X] 1443B Saving the City dp, greedy, math, sortings
11. [ ] 1360E Polygon dp, graphs, implementation, shortest paths

greedy

1. [ ] 1726C Jatayu’s Balanced Bracket Sequence data structures, dsu, graphs, greedy
2. [X] 1676F Longest Strikedata structures, greedy, implementation, sortings, two pointers
3. [ ] 1574C Slay the Dragon binary search, greedy, sortings, ternary search
4. [X] 1498B Box Fitting binary search, bitmasks, data structures, greedy
5. [ ] 1759C Thermostat greedy, math, shortest paths
6. [X] 1807G2 Subsequence Addition (Hard Version) bitmasks, dp, greedy, implementation, sortings
7. [X] 1807G1 Subsequence Addition (Easy Version) brute force, data structures, dp, greedy, implementation, sortings
8. [X] 1825B LuoTianyi and the Table greedy, math
9. [X] 1834C Game with Reversing games, greedy, math, strings
10. [ ] 1846C Rudolf and the Another Competition constructive algorithms, data structures, dp, greedy, sortings
11. [X] 1859C Another Permutation Problem brute force, dp, greedy, math
12. [X] 1810C Make It Permutationbrute force, greedy, sortings
13. [X] 1717C Madoka and Formal Statement greedy
14. [X] 1693A Directional Increase greedy
15. [X] 1649B Game of Ball Passing greedy, implementation
16. [X] 1627B Not Sitting games, greedy, sortings
17. [X] 1585C Minimize Distance greedy
18. [X] 1561C Deep Down Below binary search, greedy, sortings
19. [X] 1476B Inflationbinary search, brute force, greedy, math
20. [X] 1422B Nice Matrix greedy, implementation, math
21. [X] 1418B Negative Prefixes greedy, sortings
22. [X] 1407B Big Vova brute force, greedy, math, number theory
23. [X] 1372B Omkar and Last Class of Math greedy, math, number theory
24. [X] 1371C A Cookie for You greedy, implementation, math
25. [X] 1364B Most socially-distanced subsequence greedy, two pointers
26. [X] 1802B Settlement of Guinea Pigs greedy, implementation, math
27. [X] 1804B Vaccination greedy, implementation
28. [X] 1809B Points on Plane binary search, greedy, math
29. [X] 1811C Restore the Array constructive algorithms, greedy
30. [X] 1821B Sort the Subarray brute force, greedy
31. [X] 1834B Maximum Strength greedy, math
32. [X] 1836B Astrophysicists greedy, math
33. [X] 1837C Best Binary String constructive algorithms, greedy
34. [X] 1847B Hamon Odyssey bitmasks, greedy, two pointers
35. [X] 1859B Olya and Game with Arrays constructive algorithms, greedy, math, sortings

number theory

1902C Insert and Equalizebrute force, constructive algorithms, greedy, math, number theory Submit Add to favourites 1300 x9772 1899D Yarik and Musical Noteshashing, math, number theory Submit Add to favourites 1300 x10244 1881D Divide and Equalizemath, number theory Submit Add to favourites 1300 x11796 1864C Divisor Chainbitmasks, constructive algorithms, math, number theory Submit Add to favourites 1300 x11689 1850F We Were Both Childrenbrute force, implementation, math, number theory Submit Add to favourites 1300 x15338 1826C Dreaming of Freedomgreedy, math, number theory Submit Add to favourites 1300 x11802 1823C Strongly Compositegreedy, math, number theory Submit Add to favourites 1300 x10876 1603A Di-visible Confusionconstructive algorithms, math, number theory Submit Add to favourites 1300 x15673 1601A Array Eliminationbitmasks, greedy, math, number theory Submit Add to favourites 1300 x12405 1521B Nastia and a Good Arrayconstructive algorithms, math, number theory Submit Add to favourites 1300 x20042 1454D Number into Sequenceconstructive algorithms, math, number theory Submit Add to favourites 1300 x19106 1407B Big Vovabrute force, greedy, math, number theory Submit Add to favourites 1300 x16374 1401C Mere Arrayconstructive algorithms, math, number theory, sortings Submit Add to favourites 1300 x22791 1372B Omkar and Last Class of Mathgreedy, math, number theory Submit Add to favourites 1300 x25064 1360D Buying Shovelsmath, number theory Submit Add to favourites 1300 x29213 1294C Product of Three Numbersgreedy, math, number theory Submit Add to favourites 1300 x30355 1220B Multiplication Tablemath, number theory Submit Add to favourites 1300 x11166 1209B Koala and Lightsimplementation, math, number theory Submit Add to favourites 1300 x7821 1174C Ehab and a Special Coloring Problemconstructive algorithms, number theory Submit Add to favourites 1300 x11659 1155C Alarm Clocks Everywheremath, number theory Submit Add to favourites 1300 x8562 1113B Sasha and Magnetic Machinesgreedy, number theory Submit Add to favourites 1300 x7598 912B New Year’s Evebitmasks, constructive algorithms, number theory Submit Add to favourites 1300 x10923 900B Position in Fractionmath, number theory Submit Add to favourites 1300 x7514 876B Divisiblity of Differencesimplementation, math, number theory Submit Add to favourites 1300 x8393 870C Maximum splittingdp, greedy, math, number theory Submit Add to favourites 1300 x8735 840A Leha and Functioncombinatorics, greedy, math, number theory, sortings Submit Add to favourites 1300 x6902 633B A Trivial Problembrute force, constructive algorithms, math, number theory Submit Add to favourites 1300 x6428 573A Bear and Pokerimplementation, math, number theory Submit Add to favourites 1300 x15666 519C A and B and Team Traininggreedy, implementation, math, number theory Submit Add to favourites 1300 x18913 515B Drazil and His Happy Friendsbrute force, dsu, meet-in-the-middle, number theory Submit Add to favourites 1300 x7271 371B Fox Dividing Cheesemath, number theory Submit Add to favourites 1300 x10582 271B Prime Matrixbinary search, brute force, math, number theory Submit Add to favourites 1300 x11940 236B Easy Number Challengeimplementation, number theory Submit Add to favourites 1300 x12869 230B T-primesbinary search, implementation, math, number theory Submit Add to favourites 1300 x65551 158D Ice Sculptures*special problem, brute force, number theory Submit Add to favourites 1300 x6125 123A Prime Permutationimplementation, number theory, strings Submit Add to favourites 1300 x3459

Problem List 1400

number theory

1875C Jellyfish and Green Applebitmasks, greedy, math, number theory x9626 1866B Battling with Numberscombinatorics, math, number theory x6512 1844D Row Majorconstructive algorithms, greedy, math, number theory, strings x10950 1838C No Prime Differencesconstructive algorithms, math, number theory x12478 1759D Make It Roundbrute force, number theory x11000 1758C Almost All Multiplesgreedy, number theory x12015 1714E Add Modulo 10brute force, math, number theory x14114 1627C Not Assigningconstructive algorithms, dfs and similar, number theory, trees x13541 1609C Complex Market Analysisbinary search, dp, implementation, number theory, schedules, two pointers x9249 1606C Banknotesgreedy, number theory x13272 1526B I Hate 1111dp, math, number theory x26907 1519C Berland Regionalbrute force, data structures, greedy, number theory, sortings x15306 1462D Add to Neighbour and Removegreedy, math, number theory x15702 1370C Number Gamegames, math, number theory x22731 1350B Orac and Modelsdp, math, number theory x19739 1332B Composite Coloringbrute force, constructive algorithms, greedy, math, number theory x16698 1312C Adding Powersbitmasks, greedy, implementation, math, number theory, ternary search x15436 1285C Fadi and LCMbrute force, math, number theory x20935 1266C Diverse Matrixconstructive algorithms, greedy, math, number theory x9188 1263C Everyone is a Winner!binary search, math, meet-in-the-middle, number theory x13012 1200C Round Corridormath, number theory x9454 1091C New Year and the Sphere Transmissionmath, number theory x9226 937B Vile Grasshoppersbrute force, math, number theory x6712 762A k-th divisormath, number theory x17054 757B Bash’s Big Daygreedy, math, number theory x9484 414B Mashmokh and ACMcombinatorics, dp, number theory x19755 337B Routine Problemgreedy, math, number theory x8869 284A Cows and Primitive Rootsimplementation, math, number theory x6234 248B Chilly Willymath, number theory x5093 150A Win or Freezegames, math, number theory x7447

Problem List 1500

number theory

• [X] 1876B Effects of Anti Pimples combinatorics, number theory, sortings x6494
• [ ] 1858B The Walkway brute force, dp, greedy, math, number theory x9894
• [X] 1811E Living Sequence binary search, dp, math, number theory x10593
• [X] 1804C Pull Your Luck brute force, greedy, math, number theory x10826
• [X] 1744E1 Divisible Numbers (easy version) brute force, math, number theory x9448
• [X] 1732D1 Balance (Easy version) brute force, data structures, implementation, number theory x7767
• [ ] 1673C Palindrome Basis brute force, dp, math, number theory x10982

1542B Plus and Multiplyconstructive algorithms, math, number theory x20995 1538F Interesting Functionbinary search, dp, math, number theory x17496 1536C Diluc and Kaeyadata structures, dp, hashing, number theory x13112 1487D Pythagorean Triplesbinary search, brute force, math, number theory x16277 1444A Division brute force, math, number theory x12231 1397B Power Sequence brute force, math, number theory, sortings x14045 1379B Dubious Cyrptobinary search, brute force, math, number theory x12268 1242A Tile Paintingconstructive algorithms, math, number theory x12058 1195D1 Submarine in the Rybinsk Sea (easy edition)combinatorics, math, number theory x7553 1178D Prime Graphconstructive algorithms, greedy, math, number theory x6991 1133D Zero Quantity Maximizationhashing, math, number theory x10088 1110C Meaningless Operationsconstructive algorithms, math, number theory x8759 1062B Mathgreedy, math, number theory x8186 1005D Polycarp and Div 3dp, greedy, number theory x9525 891A Pride brute force, dp, greedy, math, number theory x9271 743C Vladik and fractions brute force, constructive algorithms, math, number theory x11485 742B Arpa’s obvious problem and Mehrdad’s terrible solution brute force, math, number theory x8835 707C Pythagorean Triplesmath, number theory x11946 630K Indivisibilitymath, number theory x4855 576A Vasya and Petya’s Gamemath, number theory x12598 566F Clique in the Divisibility Graphdp, math, number theory x3415 460B Little Dima and Equation brute force, implementation, math, number theory x11700 414A Mashmokh and Numbersconstructive algorithms, number theory x9479 264B Good Sequencesdp, number theory x9299 172D Calendar Reform*special problem, number theory x1359

Problem List 1400 –> 1500

greedy

Remaining

1. [X] 1903C Theofanis’ Nightmare constructive algorithms, greedy
2. [X] 1901C Add, Divide and Floor constructive algorithms, greedy, math
3. [X] 1898B Milena and Admirer greedy, math
4. [X] 1896C Matching Arrays binary search, constructive algorithms, greedy, sortings
5. [X] 1891C Smilo and Monsters binary search, constructive algorithms, greedy, sortings, two pointers
6. [X] 1883G1 Dances (Easy version) binary search, greedy, two pointers
7. [X] 1883D In Love data structures, greedy
8. [X] 1882C Card Game brute force, greedy
9. [X] 1878E Iva & Pav binary search, bitmasks, data structures, greedy
10. [X] 1875C Jellyfish and Green Apple bitmasks, greedy, math, number theory
11. [X] 1873G ABBC or BACB constructive algorithms, greedy
12. [X] 1863D Two-Colored Dominoes constructive algorithms, greedy
13. [X] 1844D Row Major constructive algorithms, greedy, math, number theory, strings
14. [X] 1840D Wooden Toy Festival binary search, greedy, sortings
15. [X] 1765N Number Reduction greedy
16. [X] 1804C Pull Your Luck brute force, greedy, math, number theory
17. [X] 1837D Bracket Coloring constructive algorithms, greedy

1860C Game on Permutation

data structures, dp, games, greedy

1858B The Walkway

brute force, dp, greedy, math, number theory

1847C Vampiric Powers, anyone?

bitmasks, brute force, dp, greedy

1845C Strong Password

binary search, dp, greedy, strings

1824A LuoTianyi and the Show

greedy, implementation

1817A Almost Increasing Subsequence

binary search, data structures, greedy

1814C Search in Parallel

constructive algorithms, greedy, sortings

1809C Sum on Subarrays

constructive algorithms, greedy, math

1800E2 Unforgivable Curse (hard version)

brute force, constructive algorithms, dfs and similar, dsu, graphs, greedy, strings

1800E1 Unforgivable Curse (easy version)

brute force, constructive algorithms, dsu, graphs, greedy, strings

1792C Min Max Sort

binary search, brute force, greedy, math, two pointers

1774B Coloring

constructive algorithms, greedy, math

1773E Easy Assembly

greedy, sortings

1767D Playoff

combinatorics, constructive algorithms, dp, greedy, math

1765K Torus Path

greedy, math

1764C Doremy’s City Construction

graphs, greedy

1761C Set Construction

• CLOSING NOTE [2024-03-22 Fri 10:00]
  Good greedy. topsort. BFS

constructive algorithms, dfs and similar, graphs, greedy

1760F Quests

• CLOSING NOTE [2024-03-21 Thu 20:18]
  Good greedy

binary search, greedy, sortings

1758C Almost All Multiples

greedy, number theory

1753A2 Make Nonzero Sum (hard version)

• CLOSING NOTE [2024-02-22 Thu 12:44]
  Good greedy. There are some corner cases. I should be more careful.

constructive algorithms, dp, greedy

1749C Number Game

• CLOSING NOTE [2024-02-22 Thu 12:46]
  Good greedy. I guess it’s a common greedy strategy.

binary search, data structures, games, greedy, implementation

1742G Orray

• CLOSING NOTE [2024-02-19 Mon 20:59]
  Good greedy. Read the problem carefully! It is OR not XOR!

bitmasks, brute force, greedy, math, sortings

1742F Smaller

• CLOSING NOTE [2024-02-15 Thu 20:58]
  Good Greedy. Use long long!

constructive algorithms, greedy, strings

1740C Bricks and Bags

• CLOSING NOTE [2024-02-15 Thu 20:18]
  greedy and constructive

constructive algorithms, games, greedy, sortings

KILL 1738C Even Number Addicts

• CLOSING NOTE [2024-02-15 Thu 20:19]
  too hard

dp, games, greedy, math

1735C Phase Shift

• CLOSING NOTE [2024-02-11 Sun 16:08]
  Good greedy. Use ufs: union find set.

dfs and similar, dsu, graphs, greedy, implementation, strings

1733D1 Zero-One (Easy Version)

• CLOSING NOTE [2024-02-11 Sun 10:00]
  Good greedy. Read problem carefully!

constructive algorithms, greedy, math

1728C Digital Logarithm

• CLOSING NOTE [2024-02-10 Sat 22:13]
  Good greedy

data structures, greedy, sortings

1722G Even-Odd XOR

• CLOSING NOTE [2024-01-30 Tue 21:53]
  constructive algorithms

bitmasks, constructive algorithms, greedy

1721C Min-Max Array Transformation

• CLOSING NOTE [2024-02-10 Sat 22:11]
  Interesting greedy problem

binary search, greedy, two pointers

1710A Color the Picture

• CLOSING NOTE [2024-02-01 Thu 23:37]
  Good greedy and constructive algorithms

constructive algorithms, greedy, math

1706C Qpwoeirut And The City

• CLOSING NOTE [2024-01-30 Tue 21:52]
  presum and dp

dp, flows, greedy, implementation

1701C Schedule Management

• CLOSING NOTE [2024-01-30 Tue 21:51]
  binary search

binary search, greedy, implementation, two pointers

1697C awoo’s Favorite Problem

• CLOSING NOTE [2024-01-24 Wed 23:51]
  Interesting greedy problem

binary search, constructive algorithms, data structures, greedy, implementation, strings, two pointers

1696C Fishingprince Plays With Array

• CLOSING NOTE [2024-02-10 Sat 21:08]
  Good greedy

constructive algorithms, greedy, implementation, math

1691C Sum of Substrings

• CLOSING NOTE [2024-01-24 Wed 23:03]
  Interesting greedy problem

brute force, constructive algorithms, greedy, math, strings

1690E Price Maximization

• CLOSING NOTE [2024-02-10 Sat 22:10]
  Good greedy problem

binary search, greedy, math, two pointers

1684C Column Swapping

• CLOSING NOTE [2024-01-23 Tue 23:43]
  brute force

brute force, constructive algorithms, greedy, implementation, sortings

1682C LIS or Reverse LIS?

• CLOSING NOTE [2024-01-23 Tue 22:43]
  greedy and constructive

constructive algorithms, greedy, implementation, math

1675E Replace With the Previous, Minimize

• CLOSING NOTE [2024-01-22 Mon 22:57]
  Good greedy problem

dsu, greedy, strings

1659C Line Empire

• CLOSING NOTE [2024-01-22 Mon 22:12]
  Interesting greedy

binary search, brute force, dp, greedy, implementation, math

1654C Alice and the Cake

• CLOSING NOTE [2024-01-22 Mon 19:46]
  greedy, but BFS

data structures, greedy, implementation, sortings

1644C Increase Subarray Sums

• CLOSING NOTE [2024-01-22 Mon 13:56]
  Interesting greedy, but DP

brute force, dp, greedy, implementation

1628A Meximum Array

• CLOSING NOTE [2024-01-21 Sun 23:31]
  Interesting greedy problem. MEX

binary search, constructive algorithms, greedy, implementation, math, two pointers

1624D Palindromes Coloring

• CLOSING NOTE [2024-01-20 Sat 17:59]
  Interesting greedy problem

binary search, greedy, sortings, strings

1621B Integers Shop

• CLOSING NOTE [2024-01-20 Sat 11:48]
  INF is not big enough. Use INFL or INT_MAX

data structures, greedy, implementation

1606C Banknotes

• CLOSING NOTE [2024-01-19 Fri 22:32]
  Interesting greedy problem

greedy, number theory

1605C Dominant Character

• CLOSING NOTE [2024-01-17 Wed 23:10]
  Interesting greedy problem

brute force, greedy, implementation, strings

1579D Productive Meeting

• CLOSING NOTE [2024-01-17 Wed 22:36]
  typical greedy.

constructive algorithms, graphs, greedy

1559D1 Mocha and Diana (Easy Version)

• CLOSING NOTE [2024-01-17 Wed 20:59]
  dsu and greedy

brute force, constructive algorithms, dsu, graphs, greedy, trees

1553D Backspace

• CLOSING NOTE [2024-01-17 Wed 19:16]
  Interesting greedy problem

dp, greedy, strings, two pointers

1552B Running for Gold

• CLOSING NOTE [2024-01-16 Tue 23:40]
  Interesting greedy problem

combinatorics, graphs, greedy, sortings

1551B2 Wonderful Coloring - 2

• CLOSING NOTE [2024-01-16 Tue 23:19]
  Good greedy problem

binary search, constructive algorithms, data structures, greedy

1548A Web of Lies

• CLOSING NOTE [2024-01-16 Tue 19:52]
  Interesting greedy problem

brute force, graphs, greedy

1540A Great Graphs

• CLOSING NOTE [2024-01-15 Mon 20:17]
  Interesting greedy problem

constructive algorithms, graphs, greedy, shortest paths, sortings

1535C Unstable String

• CLOSING NOTE [2024-01-15 Mon 00:10]
  Interesting DP

binary search, dp, greedy, implementation, strings, two pointers

1579C Ticks

• CLOSING NOTE [2024-01-14 Sun 23:39]
  Easy implementation

greedy, implementation

1519C Berland Regional

• CLOSING NOTE [2024-01-13 Sat 22:31]
  Interesting greedy problem

brute force, data structures, greedy, number theory, sortings

1517C Fillomino 2

• CLOSING NOTE [2024-01-13 Sat 21:57]
  Interesting greedy problem

constructive algorithms, dfs and similar, greedy, implementation

1516B AGAGA XOOORRR

• CLOSING NOTE [2024-01-13 Sat 21:23]
  
  1. XOR presum
  2. odd corner case

bitmasks, brute force, dp, greedy

1490F Equalize the Array

• CLOSING NOTE [2024-01-13 Sat 20:48]
  Interesting binary search

binary search, data structures, greedy, math, sortings

1506D Epic Transformation constructive algorithms, data structures, greedy

• CLOSING NOTE [2024-01-12 Fri 22:13]
  typical greedy problem

1494B Berland Crossword

• CLOSING NOTE [2024-01-12 Fri 23:05]
  Brute forces & DFS

bitmasks, brute force, greedy, implementation

1492C Maximum width

• CLOSING NOTE [2024-01-12 Fri 23:54]
  Interesting greedy problem

binary search, data structures, dp, greedy, two pointers

KILL 1487C Minimum Ties

• CLOSING NOTE [2024-01-18 Thu 19:36]
  Too hard for me currently
• Note taken on [2024-01-13 Sat 21:58]
  Too hard
• Note taken on [2024-01-12 Fri 23:55]
  Too hard

brute force, constructive algorithms, dfs and similar, graphs, greedy, implementation, math

1573B Swaps

• CLOSING NOTE [2024-01-11 Thu 23:45]
  Easy greedy

greedy, math, sortings

1551C Interesting Story

• CLOSING NOTE [2024-01-11 Thu 23:09]
  Good greedy problem

greedy, sortings, strings

1526C1 Potions (Easy Version)

• CLOSING NOTE [2024-01-11 Thu 21:26]
  Good DP

brute force, data structures, dp, greedy

1515D Phoenix and Socks

• CLOSING NOTE [2024-01-11 Thu 20:47]
  Interesting problem.

  Check odd/even situations.

greedy, sortings, two pointers

1466D 13th Labour of Heracles

• CLOSING NOTE [2024-01-10 Wed 22:18]
  Problem description is difficult to understand. But it’s intuitive to find the solution.

data structures, greedy, sortings, trees

1520E Arranging The Sheep

• CLOSING NOTE [2024-01-10 Wed 21:39]
  Find the middle number

greedy, math

1515C Phoenix and Towers

• CLOSING NOTE [2024-01-10 Wed 19:52]
  Guess the solution and it passed!

constructive algorithms, data structures, greedy

1499C Minimum Grid Path

• CLOSING NOTE [2024-01-10 Wed 19:32]
  It is not hard to implement. It is also intuitive to prove.
• Note taken on [2024-01-10 Wed 00:03]
  Find the minimum of sum(c_i * len_i), sum(len_i) = n

brute force, data structures, greedy, math

1490E Accidental Victory

• CLOSING NOTE [2024-01-09 Tue 23:36]
  O(n) greedy 只需要判定最好情况下，一个人能否获胜。

binary search, data structures, greedy

1462D Add to Neighbour and Remove

• CLOSING NOTE [2024-01-09 Tue 22:37]
  发现操作的性质，最终每一段的和是总和的因数，接下来就是判定问题。

greedy, math, number theory

1452B Toy Blocks

binary search, greedy, math, sortings

1451C String Equality

dp, greedy, hashing, implementation, strings

1443C The Delivery Dilemma

binary search, greedy, sortings

1431D Used Markers

special problem, greedy

1427B Chess Cheater

greedy, implementation, sortings

1426D Non-zero Segments

constructive algorithms, data structures, greedy, sortings

1833D Flipper

• CLOSING NOTE [2024-01-09 Tue 19:58]
  题解的边界处理比较漂亮，直接抄过来了

brute force, constructive algorithms, greedy

constructive algorithms

1463B Find The Array

• CLOSING NOTE [2024-01-09 Tue 20:43]
  神奇构造题。利用奇数位置的和与偶数位置的和的性质。

bitmasks, constructive algorithms, greedy

Uva

Count
29

LeetCode

DP

Divides 1

410

• CLOSING NOTE [2024-03-16 Sat 23:05]

813

• CLOSING NOTE [2024-03-16 Sat 23:05]

1278

• CLOSING NOTE [2024-03-16 Sat 23:05]

1335

• CLOSING NOTE [2024-03-16 Sat 23:05]

2478

• CLOSING NOTE [2024-03-16 Sat 23:05]

2911

• CLOSING NOTE [2024-03-16 Sat 23:05]

Divides 2

132

• CLOSING NOTE [2024-03-16 Sat 23:06]

2707

• CLOSING NOTE [2024-03-16 Sat 23:06]

2767

• CLOSING NOTE [2024-03-16 Sat 23:06]

1105

• CLOSING NOTE [2024-03-16 Sat 23:06]

2547

• CLOSING NOTE [2024-03-16 Sat 23:36]

2463

• CLOSING NOTE [2024-03-18 Mon 22:46]

[ ] 2977

Divide and Conquer

LCR 170

LCR 170. 交易逆序对的总数

• CLOSING NOTE [2024-01-10 Wed 23:55]
  Merge sort

CodeChef

contest

starters-116-div4

A Minimum Wage

• CLOSING NOTE [2024-01-11 Thu 11:05]
  Easy

B Hattrick

• CLOSING NOTE [2024-01-11 Thu 11:15]
  Easy

C Access Control

• CLOSING NOTE [2024-01-11 Thu 11:23]
  Easy

D ORST

• CLOSING NOTE [2024-01-11 Thu 11:32]
  Easy

KILL E Chef Product

• CLOSING NOTE [2024-01-18 Thu 19:35]
  It is a little hard for me currently
• Note taken on [2024-01-13 Sat 20:20]
  Too hard

vjudge

动态规划与贪心

https://vjudge.net/contest/605992#overview

P - 最大子段和

• CLOSING NOTE [2024-01-30 Tue 21:50]
  Basic DP

F - LCS

• CLOSING NOTE [2024-01-30 Tue 21:50]
  Basic DP