Number of Groups
Easy Accuracy: 13.73% Submissions: 51 Points: 2

Given an array Arr[] of N distinct integers. Write a program to find the count of groups of 2 or 3 integers that can be formed by choosing integers from the given array such that sum of integers in each of the group is divisible by three.

Example 1:

Input:
N = 4
Arr[] = {1, 2, 3, 5}
Output:
4
Explanation:
There are only 4 possible groups: (1,2,3);
(1,2) ; (1,5) ; (1,3,5)

Example 2:

Input:
N = 3
Arr[] = {1, 1, 1}
Output:
1
Explanation:
There is only 1 possible group: (1,1,1).

You don't need to read input or print anything. Your task is to complete the function noOfGroups() which takes an Integer N and an array Arr as input and returns the answer.

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(N)

Constraints:
1 <= N <= 105
1 <= Arr[i] <= 105

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