Easy Level

• Find all triplets with zero sum

• Generate all binary strings from given pattern

• Count of strings that can be formed using a, b and c under given constraints

• Find largest word in dictionary by deleting some characters of given string

• Find subarray with given sum | Set 1 (Nonnegative Numbers)

• Find the longest substring with k unique characters in a given string

• Find the two non-repeating elements in an array of repeating elements

• Flood fill Algorithm - how to implement fill() in paint?

• Meta Strings (Check if two strings can become same after a swap in one string)

• Print all Jumping Numbers smaller than or equal to a given value

• Sum of all the numbers that are formed from root to leaf paths

• The Celebrity Problem

• Unbounded Knapsack (Repetition of items allowed)

• Medium Level

• Backtracking | Set 7 (Sudoku)

• Boggle | Set 2 (Using Trie)

• Check if a Binary Tree contains duplicate subtrees of size 2 or more

• Dynamic Programming | Set 33 (Find if a string is interleaved of two other stri

• Connect nodes at same level

• Count BST nodes that lie in a given range

• Dynamic Programming | Set 11 (Egg Dropping Puzzle)

• Dynamic Programming | Set 28 (Minimum insertions to form a palindrome)

• Dynamic Programming | Set 31 (Optimal Strategy for a Game)

• Dynamic Programming | Set 32 (Word Break Problem)

• Find four elements that sum to a given value | Set 2 ( O(n^2Logn) Solution)

• Given a matrix of ‘O’ and ‘X’, replace 'O' with 'X' if surrounded by 'X'

• How to print maximum number of A's using given four keys

• Inplace rotate square matrix by 90 degrees | Set 1

• Maximum absolute difference between sum of two contiguous sub-arrays

• Merge two BSTs with limited extra space

• Merge Overlapping Intervals

• Modular Exponentiation (Power in Modular Arithmetic)

• Paper Cut into Minimum Number of Squares | Set 2

• Sum of bit differences among all pairs

• Hard Level

• Allocate minimum number of pages

• Given an array arr[], find the maximum j - i such that arr[j] > arr[i]

• Given a sorted dictionary of an alien language, find order of characters

• Hungarian Algorithm for Assignment Problem | Set 1 (Introduction)

• Implement LRU Cache

• Length of the longest valid substring

• Median in a stream of integers (running integers)

• Sum of bit differences among all pairs

• Travelling Salesman Problem | Set 1 (Naive and Dynamic Programming)

• Word Break Problem using Backtracking