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