Problems # Status Problem Level Completes Likes 106 Lexicographically previous permutation With One swap Medium % 0 107 Find all unique combinations of exact K numbers (from 1 to 9 ) with sum to N Medium % 0 108 Hamming Distance between two given integers Beginner % 0 109 Print boundary of given matrix/2D array. Beginner % 0 110 Depth-First Search (DFS) in 2D Matrix/2D-Array - Iterative Solution Beginner % 0 111 Breadth-First Search (BFS) in 2D Matrix/2D-Array Beginner % 0 112 Check the completeness of given binary tree | Set 1 - Using Node Count Medium % 0 113 Longest substring with at most K unique characters Medium % 1 114 Find all the Armstrong numbers in the given range Beginner % 0 115 Collatz Conjecture - Maximum Steps takes to transform (1, N) to 1. Medium % 0 116 Number of Islands using BFS Medium % 0 117 Check if Graph is Bipartite - Adjacency List using Depth-First Search(DFS) Hard % 0 118 Check if the given binary tree is Full or not. Beginner % 0 119 Check if given undirected graph is connected or not Beginner % 0 120 Given Graph - Remove a vertex and all edges connect to the vertex Medium % 0 121 Print Stack in reverse order. Beginner % 0 122 Sort a given stack - Using Recursion Hard % 0 123 Number's Complement - 2 Approaches Medium % 0 124 Print all subsets of an array with a sum equal to zero Medium % 0 125 Social Network Problem Hard % 0 126 Maximum number edges to make Acyclic Undirected/Directed Graph Beginner % 0 127 Evaluation of Prefix Expressions (Polish Notation) | Set 2 Medium % 0 128 Hamming Distance between two given strings Beginner % 0 129 Breadth-First Search in Disconnected Graph Medium % 0 130 ZigZag OR Diagonal traversal in 2d array/Matrix using queue Medium % 0 131 Check if Number is divisible by its digits Beginner % 0 132 Check if the given number is Armstrong number or not Beginner % 0 133 Evaluation of Prefix Expressions (Polish Notation) | Set 1 Medium % 0 134 Minimum Boats Required to rescue people Medium % 0 135 Number of Islands Medium % 0 136 Minimum No of operations required to convert a given number to 1 - Integer Replacement Problem. Medium % 0 137 Evaluation of Postfix Expressions (Polish Postfix notation) | Set 2 Medium % 0 138 Evaluation of Postfix Expressions (Polish Postfix notation) | Set 1 Medium % 0 139 Find all the numbers in the range which has prime set bits. Beginner % 0 140 Check if Graph is Bipartite - Adjacency Matrix using Depth-First Search(DFS) Hard % 0 Lexicographically previous permutation With One swap Find all unique combinations of exact K numbers (from 1 to 9 ) with sum to N Hamming Distance between two given integers Print boundary of given matrix/2D array. Depth-First Search (DFS) in 2D Matrix/2D-Array - Iterative Solution Breadth-First Search (BFS) in 2D Matrix/2D-Array Check the completeness of given binary tree | Set 1 - Using Node Count Longest substring with at most K unique characters Find all the Armstrong numbers in the given range Collatz Conjecture - Maximum Steps takes to transform (1, N) to 1. Number of Islands using BFS Check if Graph is Bipartite - Adjacency List using Depth-First Search(DFS) Check if the given binary tree is Full or not. Check if given undirected graph is connected or not Given Graph - Remove a vertex and all edges connect to the vertex Print Stack in reverse order. Sort a given stack - Using Recursion Number's Complement - 2 Approaches Print all subsets of an array with a sum equal to zero Social Network Problem Maximum number edges to make Acyclic Undirected/Directed Graph Evaluation of Prefix Expressions (Polish Notation) | Set 2 Hamming Distance between two given strings Breadth-First Search in Disconnected Graph ZigZag OR Diagonal traversal in 2d array/Matrix using queue Check if Number is divisible by its digits Check if the given number is Armstrong number or not Evaluation of Prefix Expressions (Polish Notation) | Set 1 Minimum Boats Required to rescue people Number of Islands Minimum No of operations required to convert a given number to 1 - Integer Replacement Problem. Evaluation of Postfix Expressions (Polish Postfix notation) | Set 2 Evaluation of Postfix Expressions (Polish Postfix notation) | Set 1 Find all the numbers in the range which has prime set bits. Check if Graph is Bipartite - Adjacency Matrix using Depth-First Search(DFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16