countGoodTriplets.js

/**
Given an array of integers arr, and three integers a, b and c. You need to find the number of good triplets.

A triplet (arr[i], arr[j], arr[k]) is good if the following conditions are true:

0 <= i < j < k < arr.length
|arr[i] - arr[j]| <= a
|arr[j] - arr[k]| <= b
|arr[i] - arr[k]| <= c
Where |x| denotes the absolute value of x.

Return the number of good triplets.

Example 1:
Input: arr = [3,0,1,1,9,7], a = 7, b = 2, c = 3
Output: 4
Explanation: There are 4 good triplets: [(3,0,1), (3,0,1), (3,1,1), (0,1,1)].

Example 2:
Input: arr = [1,1,2,2,3], a = 0, b = 0, c = 1
Output: 0
Explanation: No triplet satisfies all conditions.
 
Constraints:
3 <= arr.length <= 100
0 <= arr[i] <= 1000
0 <= a, b, c <= 1000

* @param {number[]} arr
* @param {number} a
* @param {number} b
* @param {number} c
* @return {number}
*/
var countGoodTriplets = function (arr, a, b, c) {
  let count = 0;
  for (let i = 0; i < arr.length - 2; i++) {
    for (let j = i + 1; j < arr.length - 1; j++) {
      for (let k = j + 1; k < arr.length; k++) {
        if (
          Math.abs(arr[i] - arr[j]) <= a &&
          Math.abs(arr[j] - arr[k]) <= b &&
          Math.abs(arr[i] - arr[k]) <= c
        ) {
          count += 1; // Found a good triplet
        }
      }
    }
  }
  return count;
};