Divisible-Sum-Pairs/Solution.java

 import java.io.*;

import java.math.*;

import java.security.*;

import java.text.*;

import java.util.*;

import java.util.concurrent.*;

import java.util.function.*;

import java.util.regex.*;

import java.util.stream.*;

import static java.util.stream.Collectors.joining;

import static java.util.stream.Collectors.toList;

class Result {

    /*

     * Complete the 'divisibleSumPairs' function below.

     *

     * The function is expected to return an INTEGER.

     * The function accepts following parameters:

     *  1. INTEGER n

     *  2. INTEGER k

     *  3. INTEGER_ARRAY ar

     */

    public static int divisibleSumPairs(int n, int k, List<Integer> ar) {

    // Write your code here

        int count=0;

        for (int i = 0 ;i<n-1;i++) {

            for (int j=i+1;j<n;j++) {

                if ((ar.get(i) + ar.get(j)) % k == 0)

                    count ++;

            }

        }

        

        return count;

    }

}

public class Solution {

    public static void main(String[] args) throws IOException {

        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        String[] firstMultipleInput = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");

        int n = Integer.parseInt(firstMultipleInput[0]);

        int k = Integer.parseInt(firstMultipleInput[1]);

        List<Integer> ar = Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))

            .map(Integer::parseInt)

            .collect(toList());

        int result = Result.divisibleSumPairs(n, k, ar);

        bufferedWriter.write(String.valueOf(result));

        bufferedWriter.newLine();

        bufferedReader.close();

        bufferedWriter.close();

    }

}