Java Comparator Hackerrank Solution

Java Comparator Hackerrank Solution

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.

Constraints

• 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

Code Solution:

//Java Comparator Hackerrank Solution

import java.util.*;

// Write your Checker class here

class Checker implements Comparator<Player>{
    @Override
    public int compare(Player a, Player b){
        if (a.score == b.score){
            return a.name.compareTo(b.name);//alphabetically
        } else {
            return b.score - a.score;//decreasing 
        }
    }
}

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);
        }
    }
}

//Java Comparator Hackerrank Solution

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