diff --git a/.vscode/c_cpp_properties.json b/.vscode/c_cpp_properties.json
new file mode 100644
index 000000000..cea4d3f4e
--- /dev/null
+++ b/.vscode/c_cpp_properties.json
@@ -0,0 +1,18 @@
+{
+  "configurations": [
+    {
+      "name": "windows-gcc-x64",
+      "includePath": [
+        "${workspaceFolder}/**"
+      ],
+      "compilerPath": "gcc",
+      "cStandard": "${default}",
+      "cppStandard": "${default}",
+      "intelliSenseMode": "windows-gcc-x64",
+      "compilerArgs": [
+        ""
+      ]
+    }
+  ],
+  "version": 4
+}
\ No newline at end of file
diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 000000000..1d43f8347
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,24 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "C/C++ Runner: Debug Session",
+      "type": "cppdbg",
+      "request": "launch",
+      "args": [],
+      "stopAtEntry": false,
+      "externalConsole": true,
+      "cwd": "e:/Learning/S30/PreCourse-1",
+      "program": "e:/Learning/S30/PreCourse-1/build/Debug/outDebug",
+      "MIMode": "gdb",
+      "miDebuggerPath": "gdb",
+      "setupCommands": [
+        {
+          "description": "Enable pretty-printing for gdb",
+          "text": "-enable-pretty-printing",
+          "ignoreFailures": true
+        }
+      ]
+    }
+  ]
+}
\ No newline at end of file
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 000000000..bb879da5a
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,59 @@
+{
+  "C_Cpp_Runner.cCompilerPath": "gcc",
+  "C_Cpp_Runner.cppCompilerPath": "g++",
+  "C_Cpp_Runner.debuggerPath": "gdb",
+  "C_Cpp_Runner.cStandard": "",
+  "C_Cpp_Runner.cppStandard": "",
+  "C_Cpp_Runner.msvcBatchPath": "C:/Program Files/Microsoft Visual Studio/VR_NR/Community/VC/Auxiliary/Build/vcvarsall.bat",
+  "C_Cpp_Runner.useMsvc": false,
+  "C_Cpp_Runner.warnings": [
+    "-Wall",
+    "-Wextra",
+    "-Wpedantic",
+    "-Wshadow",
+    "-Wformat=2",
+    "-Wcast-align",
+    "-Wconversion",
+    "-Wsign-conversion",
+    "-Wnull-dereference"
+  ],
+  "C_Cpp_Runner.msvcWarnings": [
+    "/W4",
+    "/permissive-",
+    "/w14242",
+    "/w14287",
+    "/w14296",
+    "/w14311",
+    "/w14826",
+    "/w44062",
+    "/w44242",
+    "/w14905",
+    "/w14906",
+    "/w14263",
+    "/w44265",
+    "/w14928"
+  ],
+  "C_Cpp_Runner.enableWarnings": true,
+  "C_Cpp_Runner.warningsAsError": false,
+  "C_Cpp_Runner.compilerArgs": [],
+  "C_Cpp_Runner.linkerArgs": [],
+  "C_Cpp_Runner.includePaths": [],
+  "C_Cpp_Runner.includeSearch": [
+    "*",
+    "**/*"
+  ],
+  "C_Cpp_Runner.excludeSearch": [
+    "**/build",
+    "**/build/**",
+    "**/.*",
+    "**/.*/**",
+    "**/.vscode",
+    "**/.vscode/**"
+  ],
+  "C_Cpp_Runner.useAddressSanitizer": false,
+  "C_Cpp_Runner.useUndefinedSanitizer": false,
+  "C_Cpp_Runner.useLeakSanitizer": false,
+  "C_Cpp_Runner.showCompilationTime": false,
+  "C_Cpp_Runner.useLinkTimeOptimization": false,
+  "C_Cpp_Runner.msvcSecureNoWarnings": false
+}
\ No newline at end of file
diff --git a/Exercise_1.cpp b/Exercise_1.cpp
deleted file mode 100644
index 381e274d5..000000000
--- a/Exercise_1.cpp
+++ /dev/null
@@ -1,54 +0,0 @@
-#include <bits/stdc++.h> 
-  
-using namespace std; 
-  
-#define MAX 1000 
-  
-class Stack {
-  //Please read sample.java file before starting.
-  //Kindly include Time and Space complexity at top of each file
-    int top; 
-  
-public: 
-    int a[MAX]; // Maximum size of Stack 
-  
-    Stack() { //Constructor here } 
-    bool push(int x); 
-    int pop(); 
-    int peek(); 
-    bool isEmpty(); 
-}; 
-  
-bool Stack::push(int x) 
-{ 
-    //Your code here
-    //Check Stack overflow as well
-} 
-  
-int Stack::pop() 
-{ 
-    //Your code here
-    //Check Stack Underflow as well 
-} 
-int Stack::peek() 
-{ 
-    //Your code here
-    //Check empty condition too
-} 
-  
-bool Stack::isEmpty() 
-{ 
-    //Your code here 
-} 
-  
-// Driver program to test above functions 
-int main() 
-{ 
-    class Stack s; 
-    s.push(10); 
-    s.push(20); 
-    s.push(30); 
-    cout << s.pop() << " Popped from stack\n"; 
-  
-    return 0; 
-} 
diff --git a/Exercise_1.java b/Exercise_1.java
deleted file mode 100644
index 314a3cb45..000000000
--- a/Exercise_1.java
+++ /dev/null
@@ -1,46 +0,0 @@
-class Stack { 
-    //Please read sample.java file before starting.
-  //Kindly include Time and Space complexity at top of each file
-    static final int MAX = 1000; 
-    int top; 
-    int a[] = new int[MAX]; // Maximum size of Stack 
-  
-    boolean isEmpty() 
-    { 
-        //Write your code here 
-    } 
-
-    Stack() 
-    { 
-        //Initialize your constructor 
-    } 
-  
-    boolean push(int x) 
-    { 
-        //Check for stack Overflow
-        //Write your code here
-    } 
-  
-    int pop() 
-    { 
-        //If empty return 0 and print " Stack Underflow"
-        //Write your code here
-    } 
-  
-    int peek() 
-    { 
-        //Write your code here
-    } 
-} 
-  
-// Driver code 
-class Main { 
-    public static void main(String args[]) 
-    { 
-        Stack s = new Stack(); 
-        s.push(10); 
-        s.push(20); 
-        s.push(30); 
-        System.out.println(s.pop() + " Popped from stack"); 
-    } 
-}
diff --git a/Exercise_1.js b/Exercise_1.js
deleted file mode 100644
index 207189ea0..000000000
--- a/Exercise_1.js
+++ /dev/null
@@ -1,35 +0,0 @@
-class Stack {
-  //Please read sample.java file before starting.
-  //Kindly include Time and Space complexity at top of each file
-​
-    constructor() {
-        //Initialize your constructor
-        this.MAX = 1000;
-        this.top = -1;
-        this.a = new Array(this.MAX);
-    }
-​
-    function isEmpty() {
-        //Write your code here
-    }
-​
-    function push(x) {
-        //Check for stack Overflow
-        //Write your code here
-    }
-​
-    function pop() {
-        //If empty return 0 and print " Stack Underflow"
-        //Write your code here
-    }
-​
-    function peek() {
-       //Write your code here
-    }
-}
-​
-let s = new Stack();
-s.push(10);
-s.push(20);
-s.push(30);
-console.log(s.pop() + " Popped from stack");
diff --git a/Exercise_1.py b/Exercise_1.py
index 532833f5d..135e434a4 100644
--- a/Exercise_1.py
+++ b/Exercise_1.py
@@ -1,21 +1,43 @@
+#Time complexity for this program is O(1) and for show() it will O(n)
+#Space complexity for this program is O(n) and n is the number of elements in the stack
+
 class myStack:
   #Please read sample.java file before starting.
   #Kindly include Time and Space complexity at top of each file
      def __init__(self):
+          self.stack = []
+          self.top = -1
          
      def isEmpty(self):
+          return self.top == -1
          
      def push(self, item):
-         
+          self.top +=1
+          self.stack.append(it)         
      def pop(self):
+          if self.isEmpty():
+               print("Stack is empty")
+               return None
+          item = self.stack[self.top]
+          self.top -= 1
+          return item
+               
         
         
      def peek(self):
+          if self.isEmpty():
+               print("Stack is empty")
+               return None
+          return self.stack[self.top]
         
      def size(self):
-         
+         return self.top + 1
      def show(self):
-         
+          if self.isEmpty():
+               print("Stack is empty: Nothing to show.")
+               return []
+          return self.stack[:self.top + 1]
+          
 
 s = myStack()
 s.push('1')
diff --git a/Exercise_2.cpp b/Exercise_2.cpp
deleted file mode 100644
index 1eb3de9b9..000000000
--- a/Exercise_2.cpp
+++ /dev/null
@@ -1,52 +0,0 @@
-#include <bits/stdc++.h> 
-using namespace std; 
-  
-// A structure to represent a stack 
-class StackNode { 
-public: 
-    int data; 
-    StackNode* next; 
-}; 
-  
-StackNode* newNode(int data) 
-{ 
-    StackNode* stackNode = new StackNode(); 
-    stackNode->data = data; 
-    stackNode->next = NULL; 
-    return stackNode; 
-} 
-  
-int isEmpty(StackNode* root) 
-{ 
-    //Your code here 
-} 
-  
-void push(StackNode** root, int data) 
-{ 
-    //Your code here 
-} 
-  
-int pop(StackNode** root) 
-{ 
-    //Your code here 
-} 
-  
-int peek(StackNode* root) 
-{ 
-    //Your code here 
-} 
-  
-int main() 
-{ 
-    StackNode* root = NULL; 
-  
-    push(&root, 10); 
-    push(&root, 20); 
-    push(&root, 30); 
-  
-    cout << pop(&root) << " popped from stack\n"; 
-  
-    cout << "Top element is " << peek(root) << endl; 
-  
-    return 0; 
-} 
\ No newline at end of file
diff --git a/Exercise_2.java b/Exercise_2.java
deleted file mode 100644
index 5a9c4868c..000000000
--- a/Exercise_2.java
+++ /dev/null
@@ -1,52 +0,0 @@
-public class StackAsLinkedList { 
-  
-    StackNode root; 
-  
-    static class StackNode { 
-        int data; 
-        StackNode next; 
-  
-        StackNode(int data) 
-        { 
-            //Constructor here 
-        } 
-    } 
-    
-	
-    public boolean isEmpty() 
-    { 
-        //Write your code here for the condition if stack is empty. 
-    } 
-  
-    public void push(int data) 
-    { 
-        //Write code to push data to the stack. 
-    } 
-  
-    public int pop() 
-    { 	
-	//If Stack Empty Return 0 and print "Stack Underflow"
-        //Write code to pop the topmost element of stack.
-	//Also return the popped element 
-    } 
-  
-    public int peek() 
-    { 
-        //Write code to just return the topmost element without removing it.
-    } 
-  
-	//Driver code
-    public static void main(String[] args) 
-    { 
-  
-        StackAsLinkedList sll = new StackAsLinkedList(); 
-  
-        sll.push(10); 
-        sll.push(20); 
-        sll.push(30); 
-  
-        System.out.println(sll.pop() + " popped from stack"); 
-  
-        System.out.println("Top element is " + sll.peek()); 
-    } 
-} 
diff --git a/Exercise_2.js b/Exercise_2.js
deleted file mode 100644
index 2e3216f94..000000000
--- a/Exercise_2.js
+++ /dev/null
@@ -1,36 +0,0 @@
-class StackAsLinkedList {
-​
-    static stackNode = class {
-​
-        constructor(d) {
-            //Constructor here
-            this.data = d;
-            this.next = null;
-        }
-    }
-​
-    function isEmpty() {
-        //Write your code here for the condition if stack is empty.
-    }
-​
-    function push(data) {
-       //Write code to push data to the stack.
-    }
-​
-    function pop() {
-       //If Stack Empty Return 0 and print "Stack Underflow"
-       //Write code to pop the topmost element of stack.
-       //Also return the popped element
-    }
-​
-    function peek() {
-       //Write code to just return the topmost element without removing it.
-    }
-}
-//Driver code
-const sll = new StackAsLinkedList();
-sll.push(10);
-sll.push(20);
-sll.push(30);
-console.log(sll.pop() + " popped from stack");
-console.log("Top element is " + sll.peek());
diff --git a/Exercise_2.py b/Exercise_2.py
index b11492215..a6ffb253d 100644
--- a/Exercise_2.py
+++ b/Exercise_2.py
@@ -1,4 +1,5 @@
-
+#Time complexity for this program is O(1)
+#Space complexity for this program is O(n), where n is number of elements in stack
 class Node:
     def __init__(self, data):
        self.data = data
@@ -6,10 +7,19 @@ def __init__(self, data):
  
 class Stack:
     def __init__(self):
+        self.top = None
         
     def push(self, data):
+        newNode=Node(data)
+        newNode.next = self.top
+        self.top = newNode
         
     def pop(self):
+        if self.top is None:
+            return None
+        popData = self.top.data
+        self.top = self.top.next
+        return popData
         
 a_stack = Stack()
 while True:
diff --git a/Exercise_3.cpp b/Exercise_3.cpp
deleted file mode 100644
index f34d89ac1..000000000
--- a/Exercise_3.cpp
+++ /dev/null
@@ -1,80 +0,0 @@
-#include <bits/stdc++.h> 
-using namespace std; 
-  
-// A linked list node (changes) 
-class Node  
-{  
-    public: 
-    int data;  
-    Node *next;  
-};  
-  
-/* Given a reference (pointer to pointer) 
-to the head of a list and an int, inserts 
-a new node on the front of the list. */
-void push(Node** head_ref, int new_data)  
-{  
-    /* 1. allocate node */ 
-  
-    /* 2. put in the data */  
-  
-    /* 3. Make next of new node as head */ 
-  
-    /* 4. move the head to point to the new node */
-}  
-  
-/* Given a node prev_node, insert a new node after the given  
-prev_node */
-void insertAfter(Node* prev_node, int new_data)  
-{  
-    /*1. check if the given prev_node is NULL */ 
-  
-    /* 2. allocate new node */ 
-  
-    /* 3. put in the data */ 
-  
-    /* 4. Make next of new node as next of prev_node */
-  
-    /* 5. move the next of prev_node as new_node */ 
-}  
-  
-/* Given a reference (pointer to pointer) to the head  
-of a list and an int, appends a new node at the end */
-void append(Node** head_ref, int new_data)  
-{  
-    /* 1. allocate node */ 
-  
-    /* 2. put in the data */ 
-  
-    /* 3. This new node is going to be  
-    the last node, so make next of  
-    it as NULL*/  
-  
-    /* 4. If the Linked List is empty, 
-    then make the new node as head */
-  
-    /* 5. Else traverse till the last node */
-  
-    /* 6. Change the next of last node */ 
-}  
-  
-// This function prints contents of 
-// linked list starting from head  
-void printList(Node *node)  
-{  
-    //Your code here
-}  
-  
-/* Driver code*/
-int main()  
-{  
-    Node* head = NULL;   
-    append(&head, 6);  
-    push(&head, 7);  
-    push(&head, 1);    
-    append(&head, 4);    
-    insertAfter(head->next, 8);  
-    cout<<"Created Linked list is: ";  
-    printList(head);  
-    return 0;  
-}  
\ No newline at end of file
diff --git a/Exercise_3.java b/Exercise_3.java
deleted file mode 100644
index fb66d329d..000000000
--- a/Exercise_3.java
+++ /dev/null
@@ -1,70 +0,0 @@
-import java.io.*; 
-  
-// Java program to implement 
-// a Singly Linked List 
-public class LinkedList { 
-  
-    Node head; // head of list 
-  
-    // Linked list Node. 
-    // This inner class is made static 
-    // so that main() can access it 
-    static class Node { 
-  
-        int data; 
-        Node next; 
-  
-        // Constructor 
-        Node(int d) 
-        { 
-            //Write your code here 
-        } 
-    } 
-  
-    // Method to insert a new node 
-    public static LinkedList insert(LinkedList list, int data) 
-    { 
-        // Create a new node with given data 
-   
-        // If the Linked List is empty, 
-        // then make the new node as head 
-        
-            // Else traverse till the last node 
-            // and insert the new_node there 
-
-            // Insert the new_node at last node 
-        // Return the list by head 
-        
-    } 
-  
-    // Method to print the LinkedList. 
-    public static void printList(LinkedList list) 
-    {  
-        // Traverse through the LinkedList 
-   
-            // Print the data at current node 
-       
-            // Go to next node 
-    } 
-   
-    // Driver code 
-    public static void main(String[] args) 
-    { 
-        /* Start with the empty list. */
-        LinkedList list = new LinkedList(); 
-  
-        // 
-        // ******INSERTION****** 
-        // 
-  
-        // Insert the values 
-        list = insert(list, 1); 
-        list = insert(list, 2); 
-        list = insert(list, 3); 
-        list = insert(list, 4); 
-        list = insert(list, 5); 
-  
-        // Print the LinkedList 
-        printList(list); 
-    } 
-}
\ No newline at end of file
diff --git a/Exercise_3.js b/Exercise_3.js
deleted file mode 100644
index d1511f80e..000000000
--- a/Exercise_3.js
+++ /dev/null
@@ -1,49 +0,0 @@
-// Java program to implement
-// a Singly Linked List
-class LinkedList {
-    constructor() {
-        this.head = null;
-    }
-     // Linked list Node.
-     static Node = class {
-        constructor(d) {
-            this.data = d;
-            this.next = null;
-        }
-    }
-​
-     // Method to insert a new node
-    function insert(list, data) {
-        // Create a new node with given data
-​
-        // If the Linked List is empty,
-        // then make the new node as head
-​
-        // Else traverse till the last node
-        // and insert the new_node there
-​
-        // Insert the new_node at last node
-        // Return the list by head
-    }
-​
-     // Method to print the LinkedList.
-    function printList(list) {
-        // Traverse through the LinkedList
-​
-        // Print the data at current node
-​
-        // Go to next node
-    }
-}
-       // Driver code
-       /* Start with the empty list. */
-       let list = new LinkedList();
-​
-        // ******INSERTION******
-        // Insert the values
-        list.insert(list, 1);
-        list.insert(list, 2);
-        list.insert(list, 3);
-        list.insert(list, 4);
-        // Print the LinkedList
-        list.printList(list);
diff --git a/Exercise_3.py b/Exercise_3.py
index a5d466b59..589bfc715 100644
--- a/Exercise_3.py
+++ b/Exercise_3.py
@@ -1,8 +1,12 @@
+#Time Complexity is O(1) and Space Complexity is O(N). 
+
 class ListNode:
     """
     A node in a singly-linked list.
     """
     def __init__(self, data=None, next=None):
+        self.data = data
+        self.next = next
     
 class SinglyLinkedList:
     def __init__(self):
@@ -17,6 +21,14 @@ def append(self, data):
         Insert a new element at the end of the list.
         Takes O(n) time.
         """
+        newNode = ListNode(data)
+        if not self.head:
+            self.head = newNode
+            return
+        current = self.head
+        while current.next:
+            current = current.next
+        current.next = newNode    
         
     def find(self, key):
         """
@@ -24,9 +36,33 @@ def find(self, key):
         `key`. Return the element or `None` if not found.
         Takes O(n) time.
         """
+        current = self.head
+        while current:
+            if current.data == key:
+                return current
+            current = current.next
+        return None
         
     def remove(self, key):
         """
         Remove the first occurrence of `key` in the list.
         Takes O(n) time.
         """
+        current = self.head
+        previous = None
+
+        if current and current.data == key:
+            self.head = current.next
+            current = None
+            return
+        while current:
+            if current.data == key:
+                break
+            previous = current
+            current = current.next
+
+        if not current:
+            print("Key not found.")
+            return
+        previous.next = current.next
+        current = None
diff --git a/README.md b/README.md
deleted file mode 100644
index 1e1abed69..000000000
--- a/README.md
+++ /dev/null
@@ -1,11 +0,0 @@
-# PreCourse_1
-
-# All Instructions are already provided in the respective files.
-
-Exercise_1 : Implement Stack using Array.
-
-Exercise_2 : Implement Stack using Linked List.
-
-Exercise_3 : Implement Singly Linked List.
-
-*After completing the project kindly submit a pull request*
diff --git a/Sample.java b/Sample.java
deleted file mode 100644
index 1739a9cbc..000000000
--- a/Sample.java
+++ /dev/null
@@ -1,7 +0,0 @@
-// Time Complexity :
-// Space Complexity :
-// Did this code successfully run on Leetcode :
-// Any problem you faced while coding this :
-
-
-// Your code here along with comments explaining your approach