# Status Problem Level Completes Likes 1 Lexicographically next permutation With One swap Medium % 1 2 Find the number of distinct Islands OR connected components. Hard % 0 3 Check if Graph is Bipartite - Adjacency List using Depth-First Search(DFS) Hard % 0 4 Evaluation of Prefix Expressions (Polish Notation) | Set 2 Medium % 0 5 Evaluation of Prefix Expressions (Polish Notation) | Set 1 Medium % 0 6 Reverse a Stack using recursion - In Place (Without using extra memory) Hard % 1 7 Convert Prefix to Postfix Expression Medium % 0 8 Sort a given stack - Using Temporary Stack Medium % 0 9 Convert Postfix to Prefix Expression Medium % 0 10 Convert Postfix to Infix Expression Medium % 0 11 Monotone Increasing Digits Medium % 1 12 Convert Infix to Prefix Expression Medium % 0 13 Max Flow Problem - Ford-Fulkerson Algorithm Hard % 0 14 Convert Infix to Postfix Expression Medium % 0 15 Evaluation of Infix expressions Medium % 0 16 Convert Prefix to Infix Expression Medium % 0 17 Merge K sorted Linked List - Using Priority Queue Hard % 0 18 Valid Brackets – Part 2 | Stack Method Beginner % 0 19 Graph – Find Cycle in Undirected Graph using Disjoint Set (Union-Find) Hard % 0 20 Graph – Detect Cycle in a Directed Graph using colors Hard % 0 21 Graph – Detect Cycle in an Undirected Graph using DFS Medium % 0 22 Graph – Detect Cycle in a Directed Graph Medium % 1 23 Print all sub sequences of a given array Hard % 0 24 Dynamic Programming - Egg Dropping Problem Hard % 0 25 Nuts & Bolts Problem (Lock & Key problem) Beginner % 0 26 Stock Single Sell Problem - O(n) Solution Hard % 2 27 Find the element which appears maximum number of times in the array. Medium % 0 28 Find duplicates in an given array in O(n) time and O(1) extra space. Medium % 0 29 Find the last non repeating character in a given string. Beginner % 0 30 Find the last repeating character in a given string. Beginner % 0 31 Find longest Snake sequence in a given matrix Medium % 1 32 Kadane's Algorithm - Maximum Subarray Problem Medium % 1 33 Single Threaded Binary Tree Complete Implementation Hard % 0 34 Dynamic Programming - Maximum Product Cutting Problem. Medium % 1 35 Dynamic Programming - Longest Common Subsequence Medium % 0 Lexicographically next permutation With One swap Find the number of distinct Islands OR connected components. Check if Graph is Bipartite - Adjacency List using Depth-First Search(DFS) Evaluation of Prefix Expressions (Polish Notation) | Set 2 Evaluation of Prefix Expressions (Polish Notation) | Set 1 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 Postfix to Infix Expression Monotone Increasing Digits 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 Merge K sorted Linked List - Using Priority Queue Valid Brackets – Part 2 | Stack Method Graph – Find Cycle in Undirected Graph using Disjoint Set (Union-Find) Graph – Detect Cycle in a Directed Graph using colors Graph – Detect Cycle in an Undirected Graph using DFS Graph – Detect Cycle in a Directed Graph Print all sub sequences of a given array Dynamic Programming - Egg Dropping Problem Nuts & Bolts Problem (Lock & Key problem) Stock Single Sell Problem - O(n) Solution Find the element which appears maximum number of times in the array. Find duplicates in an given array in O(n) time and O(1) extra space. Find the last non repeating character in a given string. Find the last repeating character in a given string. Find longest Snake sequence in a given matrix Kadane's Algorithm - Maximum Subarray Problem Single Threaded Binary Tree Complete Implementation Dynamic Programming - Maximum Product Cutting Problem. Dynamic Programming - Longest Common Subsequence 1 2