Sorting: Comparator HackerRank Solution

Sorting: Comparator HackerRank Solution
Source : https://www.hackerrank.com/challenges/ctci-comparator-sorting

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 in the editor below. It has two fields:

1. : a string.
2. : an integer.

Given an array of Player objects, write a comparator that sorts them in order of decreasing score. If or more players have the same score, sort those players alphabetically ascending 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. In short, when sorting in ascending order, a comparator function returns if , if , and if .

For example, given Player objects with values of , we want to sort the list as .

Function Description

Declare a Checker class that implements the comparator method as described. It should sort first descending by score, then ascending by name. The code stub reads the input, creates a list of Player objects, uses your method to sort the data, and prints it out properly.

Input Format

Locked stub code in the Solution class handles the following input from stdin:

The first line contains an integer, , the number of players.
Each of the next lines contains a player's respective and , a string and an integer.

Constraints

• Two or more players can have the same name.
• Player names consist of lowercase English alphabetic letters.

Output Format

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

Sample Input

5amy 100david 100heraldo 50aakansha 75aleksa 150

Sample Output

aleksa 150amy 100david 100aakansha 75heraldo 50

Explanation

As you can see, the players are first sorted by decreasing score and then sorted alphabetically by name.

Source : https://www.hackerrank.com/challenges/ctci-comparator-sorting

Solution

	// Karthikalapati.blogspot.com
	import java.util.*;
	class Checker implements Comparator<Player> {
	@Override
	public int compare(Player p1, Player p2) {
	if (p1.score == p2.score) {
	return p1.name.compareTo(p2.name);
	} else {
	return p2.score - p1.score; // descending order
	}
	}
	}
	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);
	}
	}
	}