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Count the number of possible triangles
Medium Accuracy: 45.44% Submissions: 37906 Points: 4

Given an unsorted array arr[] of n positive integers. Find the number of triangles that can be formed with three different array elements as lengths of three sides of triangles.

Example 1:

Input:
n = 3
arr[] = {3, 5, 4}
Output:
1
Explanation:
A triangle is possible
with all the elements 5, 3 and 4.

Example 2:

Input:
n = 5
arr[] = {6, 4, 9, 7, 8}
Output:
10
Explanation:
There are 10 triangles
possible  with the given elements like
(6,4,9), (6,7,8),...

This is a function problem. You only need to complete the function findNumberOfTriangles() that takes arr[] and n as input parameters and returns the count of total possible triangles.

Expected Time Complexity: O(n2).
Expected Space Complexity: O(1).

Constraints:
3 <= n <= 103

1 <= arr[i] <= 103

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