function divisibleSumPairs(n, k, ar) {
    
    let count = 0;
    
    for(let i = 0; i < n; i++) {
        
        let temp = ar[i];
        
        for(let j = i + 1; j < n; j++) {
            
            let sum = temp + ar[j];
            
            if(sum % k == 0) {
                count += 1;
            }
        }
    }
    return count;
}

// returns the valid pairs of indexes
vector<vector<int>> getAllSolutions(vector<int>& nums, int total, int len) {
    unordered_map<int, vector<int>> map;
    vector<vector<int>> results;

    for (int i = 0; i < len; i++) {
        // Example --> 17 % 7 = 3, we need (7 - 3) = 4, then (17 + 4) % 7 = 0
        int remain = nums[i] % total;
        int complement = (total - remain) % total;

        // check if complement exists 
        if (map.find(complement) != map.end()) {
            for (int index : map[complement]) {
                results.push_back({index, i});
            }
        }

        // push again even if complement is already in the map
        map[remain].push_back(i);
    }

    return results;
}

int divisibleSumPairs(int len, int total, vector<int> nums) {
    vector<vector<int>> V = getAllSolutions(nums, total, len);
    
    return V.size();
}

int count = 0;
        for (int i = 0; i < ar.Count(); i++)
        {
            for (int j = i+1; j < ar.Count(); j++)
            {
                if (i < j && (ar[i] + ar[j])%k ==0)
                {
                    count++;
                }
            }
        }

func divisibleSumPairs(n int32, k int32, ar []int32) int32 {
	var i, j, countOfDivisibleByK int32
	for i = 0; i < n-1; i++ {
		for j = i + 1; j < n; j++ {
			if (ar[i]+ar[j])%k == 0 {
				countOfDivisibleByK++
			}
		}
	}
	return countOfDivisibleByK
}

def divisibleSumPairs(n, k, ar):
    matches = 0
    for i in range(n):
        matches += len([(x, ar[i]) for x in ar[i+1:] if (ar[i] + x) % k == 0])
    return matches