Section 1 : 0- Introduction
Section 2 : 1- Find pair that sums up to k
Section 3 : 2- First repeating character
Section 4 : 3- Remove duplicates
Section 5 : 4- Find the duplicate
Section 6 : 5- Tree depth first search
Section 7 : 6- Maximum subarray
Section 8 : 7- Reverse binary tree
Section 9 : 8- Longest substring without repeating characters
Section 10 : 9- Reverse linked list
Section 11 : 10- Peak finding
Section 12 : 11- Palindrome linked list
Section 13 : 12- Longest possible palindrome
Section 14 : 13- Get substring index
Section 15 : 14- Tree breadth first search
Section 16 : 15- Sort linked list
Section 17 : 16- Valid binary search tree
Section 18 : 17- Minimum cost path in matrix
Section 19 : 18- Balanced binary tree
Section 20 : 19- Paths in matrix
Section 21 : 20- Tree breadth first search II
Section 22 : 21- Product of array except self
Section 23 : 22- Jump to last index
Section 24 : 23- Graph depth first search
Section 25 : 24- Graph breadth first search
Section 26 : 25- String subsequences
Section 27 : 26- Valid brackets
Section 28 : 27- Flatten binary tree
Section 29 : 28- Lowest common ancestor
Section 30 : 29- Minimum in rotated sorted array
Section 31 : 30- Add two linked lists
Section 32 : 31- Ways to climb stairs
Section 33 : 32- Subsets that sum up to k
Section 34 : 33- Ways to decode
Section 35 : 34- Remove node from binary search tree
Section 36 : 35- Array permutations
Section 37 : 36- Longest common subsequence
Section 38 : 37- Longest consecutive sequence
Section 39 : 38- Edit distance
Section 40 : 39- Count sorted vowel strings
Section 41 : 40- Smallest number after removing k digits
Section 42 : 41- Merge intervals
Section 43 : 42- Insert interval
Section 44 : 43- Maximum path sum
Section 45 : 44- 0-1 Knapsack
Section 46 : 45- Shortest palindrome
Section 47 : 46- Coin change
Section 48 : 47- Word search
Section 49 : 48- N-queens
Section 50 : 49- Word ladder
Section 51 : 50- Longest increasing subsequence