# Status Problem video Level Completes Likes 525 Find the number of pairs with odd XOR Beginner % 2 499 Compare two version numbers of a software Medium % 1 473 Given an array, count the number of pairs with a given sum. Beginner % 0 471 Two Sum Problem Beginner % 0 459 Given an array, find three-element sum closest to Zero Medium % 1 451 Find the sum of overlapping elements in two sets Beginner % 0 425 Check if the given binary tree is Full or not Beginner % 1 422 Print Stack in reverse order Beginner % 0 410 Evaluation of Prefix Expressions (Polish Notation) | Set 1 Medium % 0 394 Find the maximum number present in a String Beginner % 0 390 Convert Prefix to Postfix Expression Medium % 0 389 Convert Roman Number to Integer Beginner % 0 387 Convert Postfix to Prefix Expression Medium % 0 377 Convert Postfix to Infix Expression Medium % 0 375 String to Integer (AtoI - ASCII to Integer) Beginner % 1 373 Longest substring with at most two unique characters Medium % 0 369 Find duplicates Characters in the given String Beginner % 0 368 Max Flow Problem - Ford-Fulkerson Algorithm Hard % 0 365 Convert Infix to Postfix Expression Medium % 0 364 Find three smallest elements in a given array Beginner % 0 361 Convert Prefix to Infix Expression Medium % 0 356 Check if array contains all unique or distinct numbers Beginner % 0 353 Reverse a given number Beginner % 1 352 Check if given number is perfect square - O(√N) Solution Beginner % 0 350 Find first three largest elements in a given array Beginner % 0 347 Find the nearest building which has bike | Find nearest specific vertex from source in a graph. Hard % 0 342 Find two smallest elements in a given array Beginner % 0 340 Print all Unique elements in a given array Beginner % 0 337 Find first two largest elements in a given array Beginner % 0 336 Calculate Logn base r – Java Implementation Beginner % 0 334 Dijkstra Algorithm Implementation – TreeSet Hard % 0 330 Check if Given Number is power of 2 Beginner % 1 325 Find no of reverse pairs in an array which is sorted in two parts in O(N) Medium % 1 316 Print First N Prime Numbers Beginner % 0 313 Check if two Strings are equal without using built-in function Beginner % 0 Find the number of pairs with odd XOR Compare two version numbers of a software Given an array, count the number of pairs with a given sum. Two Sum Problem Given an array, find three-element sum closest to Zero Find the sum of overlapping elements in two sets Check if the given binary tree is Full or not Print Stack in reverse order Evaluation of Prefix Expressions (Polish Notation) | Set 1 Find the maximum number present in a String Convert Prefix to Postfix Expression Convert Roman Number to Integer Convert Postfix to Prefix Expression Convert Postfix to Infix Expression String to Integer (AtoI - ASCII to Integer) Longest substring with at most two unique characters Find duplicates Characters in the given String Max Flow Problem - Ford-Fulkerson Algorithm Convert Infix to Postfix Expression Find three smallest elements in a given array Convert Prefix to Infix Expression Check if array contains all unique or distinct numbers Reverse a given number Check if given number is perfect square - O(√N) Solution Find first three largest elements in a given array Find the nearest building which has bike | Find nearest specific vertex from source in a graph. Find two smallest elements in a given array Print all Unique elements in a given array Find first two largest elements in a given array Calculate Logn base r – Java Implementation Dijkstra Algorithm Implementation – TreeSet Check if Given Number is power of 2 Find no of reverse pairs in an array which is sorted in two parts in O(N) Print First N Prime Numbers Check if two Strings are equal without using built-in function 1 2 3