Problem Brief

Nums That Are Divisible by N 🍋

INTERNOA

The agency is giving you an int num named N and an arr of ints called arr[n].

Ur task -

1. Find two nums with indices a & b (where b > a)

2. Figure out the toal of the two nums

3. Make sure the total is divisible by N

Finally, return the number of special pairs that meet the criteria outlined in tasks 1 through 3 🥂

1Example 1

Input

N = 3, arr = [5, 4, 3, 2, 1]

Output

Explanation

We can that there are FOUR pairs that meet the criteria outlined in task 1 through task 3 above 👆 arr[0] + arr[1] = 1 + 2 = 3, 3 ➗ 3 = 1 arr[0] + arr[4] = 1 + 5 = 6, 6 ➗ 3 = 2 arr[1] + arr[3] = 2 + 4 = 6, 6 ➗ 3 = 2 arr[3] + arr[4] = 4 + 5 = 9, 9 ➗ 3 = 3 So, 4 should be returned. For original prompt, pls refer source image.

Constraints

Limits and guarantees your solution can rely on.

1 <= N <= 10⁹

1 <= len of arr <= 10⁵

1 <= arr[i] <= 10⁹

Draft autosaves locally

  public int sumBeingAbletoBeDivisibleByN(int N, int[] arr) {
      // write your code here (lc1010 might help)

  }

Input

arr

[5, 4, 3, 2, 1]

Output