Valid Triangle Number:

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

Solution:

                               /**
                                * @param {number[]} nums
                                * @return {number}
                                */
                    
                                var triangleNumber = function(arr) {
                                // Count of triangles
                                let count = 0;
                                let n = arr.length;
                                
                                // The three loops select three
                                // different values from array
                                for (let i = 0; i < n; i++) {
                                    for (let j = i + 1; j < n; j++) { // The innermost loop checks for // the triangle property
                                        for (let k = j + 1; k < n; k++) // Sum of two sides is greater // than the third if ( arr[i] + arr[j]> arr[k]
                                    && arr[i] + arr[k] > arr[j]
                                                && arr[k] + arr[j] > arr[i])
                                        count++;
                                    }
                                }
                                return count;
                            };
                          

Output:

Valid Triangle Number

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