Valid Triangle Number.txt

Given an integer array nums, return the number of triplets chosen from the array that can make triangles if we take them as side lengths of a triangle.

 

Example 1:

Input: nums = [2,2,3,4]
Output: 3
Explanation: Valid combinations are: 
2,3,4 (using the first 2)
2,3,4 (using the second 2)
2,2,3
Example 2:

Input: nums = [4,2,3,4]
Output: 4
 

Constraints:

1 <= nums.length <= 1000
0 <= nums[i] <= 1000