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  1. Prepare
  2. Algorithms
  3. Implementation
  4. Divisible Sum Pairs
  5. Discussions

Divisible Sum Pairs

  • kroizer21
     + 0 comments

    C# Solution: Explanation: we sort the array, and after the array is in a non descending order, we apply the two pointer method, "i" points to the current number and "j" starts from the end and works its way backwards until the number "ar[i] + ar[j] < k" (after that there is no reason to continue, because none of the pairs will be divisible by k)

            ar.Sort();
        int answer = 0;
        int i = 0;
        int j = n-1;
        while (i < j) {
            if ((ar[i] + ar[j])%k == 0) {
                answer++;
            }
            if (ar[i] + ar[j] < k || j==i+1) {
                i++;
                j=n-1;
            } else {
                j--; 
            }
        }
        return answer;