# Status Problem video Level Completes Likes 551 Reverse a linked list using stack Medium % 0 549 Dynamic Programming - Minimum Cost for Climbing Stairs Medium % 0 548 Minimum Number of Halls Required for Lecture Scheduling Hard % 1 547 Maximum Contiguous ones after one deletion Medium % 2 546 Converting to Non-Decreasing Array with One Change Medium % 0 545 Maximizing Contiguous Ones with a Single Flip in a Binary Array Medium % 3 544 Counting the Largest Number Groups by Digit Sum Medium % 2 538 Find The Minimum time difference Medium % 1 532 Maximum Depth of Valid Nested Parentheses in an arithmetic expression Medium % 0 521 Maximum overlaps in a given list of time intervals Medium % 0 520 Remove Duplicates in a given Sorted Array Beginner % 0 518 Replace Elements with Greatest Element on Right Beginner % 0 517 Count number of pairs in an array with sum = K Medium % 0 493 Maximum meetings in one room Medium % 0 488 Check if given sudoku is valid or not Medium % 0 476 Find subarray with a sum to given number-2 | Handle negative numbers Medium % 0 473 Given an array, count the number of pairs with a given sum. Beginner % 0 468 Unique subsets with a given sum with allowed repeated digits. Medium % 0 467 Print all steps to convert one string to another string Medium % 0 466 Lexicographically next permutation With One swap Medium % 1 465 Find all subsets of size K from a given number N (1 to N) Medium % 0 463 Combinations with sum K from a given number N with repetition Medium % 0 457 Given an array, print all unique subsets with a given sum. Medium % 0 456 Subsets Elements less than K. Medium % 0 454 Find all unique combinations of numbers (from 1 to 9 ) with sum to N Medium % 0 447 Check If Given Undirected Graph is a tree Medium % 0 444 Articulation Points OR Cut Vertices in a Graph Hard % 0 443 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 % 0 439 Determine the given routing number belong to which bank Medium % 0 437 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 % 0 431 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 Reverse a linked list using stack Dynamic Programming - Minimum Cost for Climbing Stairs Minimum Number of Halls Required for Lecture Scheduling Maximum Contiguous ones after one deletion Converting to Non-Decreasing Array with One Change Maximizing Contiguous Ones with a Single Flip in a Binary Array Counting the Largest Number Groups by Digit Sum Find The Minimum time difference Maximum Depth of Valid Nested Parentheses in an arithmetic expression Maximum overlaps in a given list of time intervals Remove Duplicates in a given Sorted Array Replace Elements with Greatest Element on Right Count number of pairs in an array with sum = K Maximum meetings in one room Check if given sudoku is valid or not Find subarray with a sum to given number-2 | Handle negative numbers Given an array, count the number of pairs with a given sum. Unique subsets with a given sum with allowed repeated digits. Print all steps to convert one string to another string Lexicographically next permutation With One swap Find all subsets of size K from a given number N (1 to N) Combinations with sum K from a given number N with repetition Given an array, print all unique subsets with a given sum. Subsets Elements less than K. Find all unique combinations of numbers (from 1 to 9 ) with sum to N Check If Given Undirected Graph is a tree Articulation Points OR Cut Vertices in a Graph 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 Determine the given routing number belong to which bank Lexicographically previous permutation With One swap 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. 1 2 3 4 5 6 7