Java Comparator | HackerRank Solution

Hello coders, today we are going to solve Java Comparator HackerRank Solution.

Java Comparator

Problem

Comparators are used to compare two objects. In this challenge, you’ll create a comparator and use it to sort an array.
The Player class is provided for you in your editor. It has 2 fields: a name String and a score integer.
Given an array of n Player objects, write a comparator that sorts them in order of decreasing score; if 2 or more players have the same score, sort those players alphabetically by name. To do this, you must create a Checker class that implements the Comparator interface, then write an int compare(Player a, Player b) method implementing the Comparator.compare(T o1, T o2) method.

Input Format

Input from stdin is handled by the locked stub code in the Solution class.

The first line contains an integer, n, denoting the number of players.
Each of the n subsequent lines contains a player’s name and score, respectively.

Constraint

  • 0 <= score <= 1000
  • 2 players can have the same name.
  • Player names consist of lowercase English letters.

Output Format

You are not responsible for printing any output to stdout. The locked stub code in Solution will create a Checker object, use it to sort the Player array, and print each sorted element.

Sample Input

 5
 amy 100
 david 100
 heraldo 50
 aakansha 75
 aleksa 150

Sample Output

 aleksa 150
 amy 100
 david 100
 aakansha 75
 heraldo 50

Solution – Java Comparator

import java.util.*;

// Write your Checker class here
class Checker implements Comparator {
    public int compare(Object o1,  Object o2) {
        Player p1 = (Player) o1;
        Player p2 = (Player) o2;
        if (p2.score - p1.score == 0) return p1.name.compareTo(p2.name);
        return p2.score - p1.score;
    }
}

class Player{
    String name;
    int score;
    
    Player(String name, int score){
        this.name = name;
        this.score = score;
    }
}

class Solution {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();

        Player[] player = new Player[n];
        Checker checker = new Checker();
        
        for(int i = 0; i < n; i++){
            player[i] = new Player(scan.next(), scan.nextInt());
        }
        scan.close();
     
        Arrays.sort(player, checker);
        for(int i = 0; i < player.length; i++){
            System.out.printf("%s %s\n", player[i].name, player[i].score);
        }
    }
}

Disclaimer: The above Problem ( Java Comparator ) is generated by Hacker Rank but the Solution is Provided by CodingBroz. This tutorial is only for Educational and Learning Purpose.

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