- Find if there is a subarray with 0 sum.
- Find and print all subarray with sum = 0.
- Minimum length subarray with sum k.
- Minimum length subarray sum greater than given value (k).
- Reverse a Linked List
- Reverse a Linked List in groups of given size
- Find the intersection point of two linked lists (given head of both linked lists)
- Find first and last occurance of a number in a sorted array.
- Find the Rotation Count in Rotated Sorted array
- InOrder, PreOrder, PostOrder (Iterative & Recursive) [Refer InterviewBit]
- Height of a tree.
- Level order traversal of a tree.
- Left view of a binary tree.
- Right view of a tree.
- Top view of a tree.
- Bottom view of a tree.
- Zig-zag traversal of a tree.
- Determine if a given tree has root-to-leaf path sum adding up to given k (Path Sum).
- Path to a given node (Print path).
- Largest Smaller BST
- Valid BST
- Determine if a binary tree is height balanced or not
- *Practice Question : BST Iterator
- Find common elements in 2 sorted arrays. (Discuss)
- LCS (Longest Common Subsequence).
- Add 2 numbers represented by linked lists.
- Longest substring without repeating characters
- Length of longest substring without repeating characters
- Remove duplicates from a string in O(1) space
- Merge K sorted arrays
- Array of Array Product
- Given 2 sorted array find the pair one from each array, whose sum is closest to k.
- Find next greater number of a given number using same digits.
- Find the index next greater number in an array to the right of it.
- Trapping rain water
- Roman to Integer
- Distribute Candies (Leetcode)
- Number of Islands
- Search a word in a grid
- Find first non-repeating character in a string.
- Return all unique triplet with sum 0 (Can be asked to make it generic for k sized set)
- [LRU Cache] (https://leetcode.com/problems/lru-cache/discuss/1196636/In-case-you-are-looking-for-a-solution-for-interviews)
- Heap Implementation (Coding Ninjas Videos)
- Hashmap Implementation (CN Video)
- Union Find (Path Compression)