# Status Problem video Level Completes Likes 436 Find all unique combinations of exact K numbers (from 1 to 9 ) with sum to N Medium % 0 431 Check the completeness of given binary tree | Set 1 - Using Node Count Medium % 0 428 Collatz Conjecture - Maximum Steps takes to transform (1, N) to 1. Medium % 0 427 Number of Islands using BFS Medium % 0 426 Check if Graph is Bipartite - Adjacency List using Depth-First Search(DFS) Hard % 0 421 Sort a given stack - Using Recursion Hard % 1 419 Print all subsets of an array with a sum equal to zero Medium % 0 416 Evaluation of Prefix Expressions (Polish Notation) | Set 2 Medium % 0 410 Evaluation of Prefix Expressions (Polish Notation) | Set 1 Medium % 0 408 Number of Islands Medium % 1 407 Integer Replacement Problem Medium % 0 402 Check if Arithmetic Expression contains duplicate parenthesis Medium % 0 401 Introduction to Bipartite Graphs OR Bigraphs Medium % 0 396 Optimizing Test Execution: Managing Test Dependencies for Sequential Order Medium % 0 392 Reverse a Stack using recursion - In Place (Without using extra memory) Hard % 1 390 Convert Prefix to Postfix Expression Medium % 0 388 Sort a given stack - Using Temporary Stack Medium % 0 387 Convert Postfix to Prefix Expression Medium % 0 386 Convert Integer to Roman Medium % 0 384 Grouping of Anagrams Medium % 0 377 Convert Postfix to Infix Expression Medium % 0 372 Monotone Increasing Digits - Leetcode Medium % 1 371 Convert Infix to Prefix Expression Medium % 0 368 Max Flow Problem - Ford-Fulkerson Algorithm Hard % 0 365 Convert Infix to Postfix Expression Medium % 0 363 Evaluation of Infix expressions Medium % 0 361 Convert Prefix to Infix Expression Medium % 0 360 Least Recently Used (LRU) Cache – Using LinkedHashSet and Deque | Set 2 Hard % 0 359 Merge K sorted Linked List - Using Priority Queue Hard % 0 354 Valid Multiple Parentheses Medium % 1 353 Reverse a given number Beginner % 1 346 Valid Brackets – Part 2 | Stack Method Beginner % 0 330 Check if Given Number is power of 2 Beginner % 1 319 Get the Sum of Digits in a number till it become a single digit Medium % 0 317 Check if given number is Prime - O(√N) Solution Medium % 0 Find all unique combinations of exact K numbers (from 1 to 9 ) with sum to N Check the completeness of given binary tree | Set 1 - Using Node Count 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) Sort a given stack - Using Recursion Print all subsets of an array with a sum equal to zero Evaluation of Prefix Expressions (Polish Notation) | Set 2 Evaluation of Prefix Expressions (Polish Notation) | Set 1 Number of Islands Integer Replacement Problem Check if Arithmetic Expression contains duplicate parenthesis Introduction to Bipartite Graphs OR Bigraphs Optimizing Test Execution: Managing Test Dependencies for Sequential Order Reverse a Stack using recursion - In Place (Without using extra memory) Convert Prefix to Postfix Expression Sort a given stack - Using Temporary Stack Convert Postfix to Prefix Expression Convert Integer to Roman Grouping of Anagrams Convert Postfix to Infix Expression Monotone Increasing Digits - Leetcode Convert Infix to Prefix Expression Max Flow Problem - Ford-Fulkerson Algorithm Convert Infix to Postfix Expression Evaluation of Infix expressions Convert Prefix to Infix Expression Least Recently Used (LRU) Cache – Using LinkedHashSet and Deque | Set 2 Merge K sorted Linked List - Using Priority Queue Valid Multiple Parentheses Reverse a given number Valid Brackets – Part 2 | Stack Method Check if Given Number is power of 2 Get the Sum of Digits in a number till it become a single digit Check if given number is Prime - O(√N) Solution 1 2 3 4 5 6 7