Problems # Status Problem Level Completes Likes 1 Find the number of pairs with odd XOR Beginner % 1 2 Compare two version numbers of a software Medium % 0 3 Given an array, count the number of pairs with a given sum. Beginner % 0 4 Two Sum Problem Beginner % 0 5 Given an array, find three-element sum closest to Zero Medium % 0 6 Find the sum of overlapping elements in two sets Beginner % 0 7 Check if the given binary tree is Full or not. Beginner % 0 8 Print Stack in reverse order. Beginner % 0 9 Evaluation of Prefix Expressions (Polish Notation) | Set 1 Medium % 0 10 Find the maximum number present in a String Beginner % 0 11 Convert Prefix to Postfix Expression Medium % 0 12 Convert Roman Number to Integer Beginner % 0 13 Convert Postfix to Prefix Expression Medium % 0 14 Convert Postfix to Infix Expression Medium % 0 15 String to Integer (AtoI - ASCII to Integer) Beginner % 0 16 Longest substring with at most two unique characters Medium % 0 17 Find duplicates Characters in the given String Beginner % 0 18 Max Flow Problem - Ford-Fulkerson Algorithm Hard % 0 19 Convert Infix to Postfix Expression Medium % 0 20 Find three smallest elements in a given array Beginner % 0 21 Convert Prefix to Infix Expression Medium % 0 22 Check if array contains all unique or distinct numbers. Beginner % 0 23 Reverse a given number – Java Code Beginner % 0 24 Check if given number is perfect square - O(√N) Solution Beginner % 0 25 Find first three largest elements in a given array Beginner % 0 26 Find the nearest building which has bike | Find nearest specific vertex from source in a graph. Hard % 0 27 Find two smallest elements in a given array Beginner % 0 28 Print all Unique elements in a given array Beginner % 0 29 Find first two largest elements in a given array Beginner % 0 30 Calculate Logn base r – Java Implementation Beginner % 0 31 Dijkstra Algorithm Implementation – TreeSet and Pair Class Hard % 0 32 Check if Given Number is power of 2. Beginner % 0 33 Find no of reverse pairs in an array which is sorted in two parts in O(N) Hard % 0 34 Print First N Prime Numbers - Java Code Beginner % 0 35 Check if two Strings are equal without using built-in function - Java 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 – Java Code 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 and Pair Class 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 - Java Code Check if two Strings are equal without using built-in function - Java 1 2 3