The following list contains the most commonly asked / important questions in coding interviews.

1. Add two numbers represented by two Lists (heads are least significant digits)
2. Remove Nth node from the end of the list
3. Merge two sorted lists
4. Reverse linked list
5. Reverse LinkedList in groups of k

1. Longest substring without repeating characters
2. Longest palindromic substring
3. Maximum sum SubArray
4. Climbing stairs
5. Word break
6. House robber

1. Reverse an integer
2. Square root
3. Implement Pow(x, n)
4. Excel sheet column number
5. Count primes
6. Find median from data stream
7. Coin change

1. Container with most water
2. Valid palindrome
3. Pythagorean triplets

1. Roman to Integer
2. Longest common prefix
3. Letter combinations of a phone number
4. Valid parenthesis
5. Implement strStr

1. Remove duplicates from a sorted array
2. Search in rotated sorted array
3. Rotate image
4. Spiral matrix
5. Merge intervals
6. Sort colors
7. Merge sort an array
8. Merge two sorted arrays
9. Number of islands
10. Kth largest element in array

1. Binary tree In-order traversal
2. Binary tree level order / zig-zag level order traversal
3. Validate BST
4. Symmetric tree
5. Maximum depth of binary tree
6. Balanced binary tree (needs depth function)
7. Convert sorted array to BST (needs overloading)
8. Populating next right pointers in each node
9. Kth smallest in a BST
10. Binary tree to Doubly LinkedList

1. LRU Cache
2. Min Stack