# Status Problem Level Completes Likes 1 Counting the Largest Number Groups by Digit Sum Medium % 2 2 Duplicate even elements in an array Beginner % 1 3 Find the number of pairs with odd XOR Beginner % 2 4 Count number of pairs in an array with sum = K Medium % 0 5 Count similar words in a given array Beginner % 0 6 Find the Number of Contiguous Parking Areas Medium % 1 7 The largest number can be formed from the given number Beginner % 0 8 Print all nested directories and files in a given directory - Recursion Medium % 0 9 Maximum meetings in one room Medium % 0 10 Check if given sudoku is valid or not Medium % 0 11 Construct the Largest number from the given digits Beginner % 1 12 Efficient Robot Problem - Find Minimum Trips Hard % 0 13 Given an array, count the number of pairs with a given sum. Beginner % 0 14 Two Sum Problem Beginner % 0 15 Find if any two intervals overlap in given intervals Medium % 0 16 Find all subsets of size K from a given number N (1 to N) Medium % 0 17 Find all possible combinations with sum K from a given number N(1 to N) with the repetition of numbers is allowed Medium % 0 18 Insert a node in the given sorted linked list. Beginner % 1 19 Construct the largest number from the given array. Medium % 0 20 Find all unique combinations of numbers (from 1 to 9 ) with sum to N Medium % 0 21 Activity Selection Problem Medium % 0 22 Find the sum of overlapping elements in two sets Beginner % 0 23 Check the completeness of given binary tree | Set 2 - Using Level Order Traversal Medium % 0 24 Given an array, Print sum of all subsets Beginner % 1 25 Lexicographically previous permutation With One swap Medium % 1 26 Find all unique combinations of exact K numbers (from 1 to 9 ) with sum to N Medium % 0 27 Check the completeness of given binary tree | Set 1 - Using Node Count Medium % 0 28 Check if the given binary tree is Full or not. Beginner % 1 29 Print Stack in reverse order. Beginner % 0 30 Maximum number edges to make Acyclic Undirected/Directed Graph Beginner % 0 31 Evaluation of Prefix Expressions (Polish Notation) | Set 2 Medium % 0 32 ZigZag OR Diagonal traversal in 2d array/Matrix using queue Medium % 0 33 Evaluation of Prefix Expressions (Polish Notation) | Set 1 Medium % 0 34 Evaluation of Postfix Expressions (Polish Postfix notation) | Set 2 Medium % 0 35 Evaluation of Postfix Expressions (Polish Postfix notation) | Set 1 Medium % 0 Counting the Largest Number Groups by Digit Sum Duplicate even elements in an array Find the number of pairs with odd XOR Count number of pairs in an array with sum = K Count similar words in a given array Find the Number of Contiguous Parking Areas The largest number can be formed from the given number Print all nested directories and files in a given directory - Recursion Maximum meetings in one room Check if given sudoku is valid or not Construct the Largest number from the given digits Efficient Robot Problem - Find Minimum Trips Given an array, count the number of pairs with a given sum. Two Sum Problem Find if any two intervals overlap in given intervals Find all subsets of size K from a given number N (1 to N) Find all possible combinations with sum K from a given number N(1 to N) with the repetition of numbers is allowed Insert a node in the given sorted linked list. Construct the largest number from the given array. Find all unique combinations of numbers (from 1 to 9 ) with sum to N Activity Selection Problem Find the sum of overlapping elements in two sets Check the completeness of given binary tree | Set 2 - Using Level Order Traversal 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 Check the completeness of given binary tree | Set 1 - Using Node Count Check if the given binary tree is Full or not. Print Stack in reverse order. Maximum number edges to make Acyclic Undirected/Directed Graph Evaluation of Prefix Expressions (Polish Notation) | Set 2 ZigZag OR Diagonal traversal in 2d array/Matrix using queue Evaluation of Prefix Expressions (Polish Notation) | Set 1 Evaluation of Postfix Expressions (Polish Postfix notation) | Set 2 Evaluation of Postfix Expressions (Polish Postfix notation) | Set 1 1 2 3 4