Java Hashset HackerRank Solution

Hello Programmers, In this post, you will know how to solve the Java Hashset HackerRank Solution. This problem is a part of the HackerRank Java Programming Series.

Java Hashset HackerRank Solution
Java Hashset HackerRank Solutions

One more thing to add, don’t directly look for the solutions, first try to solve the problems of Hackerrank by yourself. If you find any difficulty after trying several times, then you can look for solutions.

Java Hashset HackerRank Solution


In computer science, a set is an abstract data type that can store certain values, without any particular order, and no repeated values(Wikipedia).  is an example of a set, but  is not a set. Today you will learn how to use sets in java by solving this problem.

You are given  pairs of strings. Two pairs  and  are identical if  and . That also implies  is not same as . After taking each pair as input, you need to print number of unique pairs you currently have.

Complete the code in the editor to solve this problem.

Input Format

In the first line, there will be an integer  denoting number of pairs. Each of the next  lines will contain two strings seperated by a single space.


  • Length of each string is atmost  and will consist lower case letters only.

Output Format

Print  lines. In the  line, print number of unique pairs you have after taking  pair as input.

Sample Input

john tom
john mary
john tom
mary anna
mary anna

Sample Output



  • After taking the first input, you have only one pair: (john,tom)
  • After taking the second input, you have two pairs: (john, tom) and (john, mary)
  • After taking the third input, you still have two unique pairs.
  • After taking the fourth input, you have three unique pairs: (john,tom), (john, mary) and (mary, anna)
  • After taking the fifth input, you still have three unique pairs.

Java Hashset HackerRank Solution

import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
public class Solution {
 public static void main(String[] args) {
        Scanner s = new Scanner(;
        int t = s.nextInt();
        String [] pair_left = new String[t];
        String [] pair_right = new String[t];
        for (int i = 0; i < t; i++) {
            pair_left[i] =;
            pair_right[i] =;
        HashSet<String> set = new HashSet(t);
        for (int i = 0; i < t; i++) {
            set.add(pair_left[i] + " " + pair_right[i]);

Disclaimer: The above Problem (Java Hashset) is generated by Hackerrank but the Solution is Provided by BrokenProgrammers. This tutorial is only for Educational and Learning purposes.

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