Count Good Triplets(LeetCode 1534):

Problem

Given an array of integers arr, and three integers ab 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