Featured Lists Top 20 Problems on Dynamic programming Top 10 Problems on Backtracking Top 20 Problems on Graph Top 25 Problems on Trees Top 10 Problems on Bits Manipulation Top 15 Problems in LinkedList All Problems # Status Problem video Level Completes Likes 446 Print all middle elements of the given matrix/2D array. Beginner % 1 445 Depth-First Search (DFS) in 2D Matrix/2D-Array - Recursive Solution Beginner % 1 443 Check the completeness of given binary tree | Set 2 - Using Level Order Traversal Medium % 0 442 Find the number of distinct Islands OR connected components. Hard % 0 441 Print All Paths in Dijkstra's Shortest Path Algorithm Hard % 0 440 Given an array, Print sum of all subsets Beginner % 1 437 Lexicographically previous permutation With One swap Medium % 1 436 Find all unique combinations of exact K numbers (from 1 to 9 ) with sum to N Medium % 0 434 Print boundary of given matrix/2D array. Beginner % 1 433 Depth-First Search (DFS) in 2D Matrix/2D-Array - Iterative Solution Beginner % 0 432 Breadth-First Search (BFS) in 2D Matrix/2D-Array Beginner % 1 430 Longest substring with at most K unique characters Medium % 2 428 Collatz Conjecture - Maximum Steps takes to transform (1, N) to 1. Medium % 0 427 Number of Islands using BFS Medium % 0 423 Given Graph - Remove a vertex and all edges connect to the vertex Medium % 0 422 Print Stack in reverse order Beginner % 0 419 Print all subsets of an array with a sum equal to zero Medium % 0 417 Maximum number edges to make Acyclic Undirected/Directed Graph Beginner % 0 415 Hamming Distance between two given strings Beginner % 0 414 Breadth-First Search in Disconnected Graph Medium % 0 407 Integer Replacement Problem Medium % 0 400 Reverse the Directed Graph Beginner % 0 399 Round Price Problem Hard % 0 397 Find Third Smallest elements in a given array Beginner % 0 396 Optimizing Test Execution: Managing Test Dependencies for Sequential Order Medium % 0 395 Implement Graph Using Map or dictionary Medium % 0 394 Find the maximum number present in a String Beginner % 0 393 Count number of subgraphs in a given graph Beginner % 0 391 Check if given an edge is a bridge in the graph Medium % 0 388 Sort a given stack - Using Temporary Stack Medium % 0 386 Convert Integer to Roman Medium % 0 385 String to Integer (AtoI - ASCII to Integer) - Recursive Solution Medium % 0 384 Grouping of Anagrams Medium % 0 380 Count the number of nodes in a given binary tree Beginner % 0 378 Longest contiguous character in a given String - O(N) Solution Beginner % 0 Print all middle elements of the given matrix/2D array. Depth-First Search (DFS) in 2D Matrix/2D-Array - Recursive Solution Check the completeness of given binary tree | Set 2 - Using Level Order Traversal Find the number of distinct Islands OR connected components. Print All Paths in Dijkstra's Shortest Path Algorithm Given an array, Print sum of all subsets Lexicographically previous permutation With One swap Find all unique combinations of exact K numbers (from 1 to 9 ) with sum to N 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 Longest substring with at most K unique characters Collatz Conjecture - Maximum Steps takes to transform (1, N) to 1. Number of Islands using BFS Given Graph - Remove a vertex and all edges connect to the vertex Print Stack in reverse order Print all subsets of an array with a sum equal to zero Maximum number edges to make Acyclic Undirected/Directed Graph Hamming Distance between two given strings Breadth-First Search in Disconnected Graph Integer Replacement Problem Reverse the Directed Graph Round Price Problem Find Third Smallest elements in a given array Optimizing Test Execution: Managing Test Dependencies for Sequential Order Implement Graph Using Map or dictionary Find the maximum number present in a String Count number of subgraphs in a given graph Check if given an edge is a bridge in the graph Sort a given stack - Using Temporary Stack Convert Integer to Roman String to Integer (AtoI - ASCII to Integer) - Recursive Solution Grouping of Anagrams Count the number of nodes in a given binary tree Longest contiguous character in a given String - O(N) Solution 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17