Divisible Sum Pairs


Problem Statement :


Given an array of integers and a positive integer k, determine the number of (i, j) pairs where i<j and ar[i] + ar[j] is divisible by k.


Example
ar = [1, 2, 3, 4, 5, 6]
k=5

Three pairs meet the criteria: [1, 4], [2, 3] and [4, 6].


Function Description

Complete the divisibleSumPairs function in the editor below.
divisibleSumPairs has the following parameter(s):

int n: the length of array 
int ar[n]: an array of integers
int k: the integer divisor

Returns
- int: the number of pairs


Input Format

The first line contains 2 space-separated integers, n and k.
The second line contains n space-separated integers, each a value of arr[i].


Constraints
2 <= n <= 100
1 <= k <=100
1 <= arr[i] <= 100


Solution :



title-img 


                            Solution in C :

python3  :

#!/bin/python3

import sys


n,k = input().strip().split(' ')
n,k = [int(n),int(k)]
a = [int(a_temp) for a_temp in input().strip().split(' ')]

result = 0
for i in range(n-1):
    for j in range(i+1, n):
        if not ((a[i] + a[j]) % k):
            result += 1
print(result)







Java  :

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
         int cnt=0;
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int k = in.nextInt();
        int a[] = new int[n];
        for(int a_i=0; a_i < n; a_i++){
            a[a_i] = in.nextInt();
        }
        for(int a_i=0; a_i < n-1; a_i++){
          for(int a_j=a_i+1; a_j< n; a_j++){
           if( (a[a_i]+a[a_j])%k==0)
               cnt++;
               
        } 
        }
        System.out.println(cnt);
    }
}







C++  :

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n;
    int k;
    int count = 0;
    cin >> n >> k;
    vector<int> a(n);
    for(int a_i = 0;a_i < n;a_i++){
       cin >> a[a_i];
    }
    
    for(int i =0 ; i < n -1 ; i++){
        for(int j=i+1 ; j < n ; j++){
            if( (a[i]+a[j])%k ==0){
                count++;
            }
        }
    }
    
    cout << count;
    return 0;
}








C :

#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int main(){
    int n; 
    int k;
    int ans = 0, i, j, t;
    scanf("%d %d",&n,&k);
    int *a = malloc(sizeof(int) * n);
    for(int a_i = 0; a_i < n; a_i++){
       scanf("%d",&a[a_i]);
    }
    for (i=0;i<n;i++)
    {
        for(j=i+1;j<n;j++)
            {
            if ((a[i]+a[j])%k==0)
                ans++;
        }
    }
    printf("%d\n",ans);
    return 0;
}








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