031. Count Good Triplets.py

"""
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)].
"""
def countGoodTriplets(self, arr, a, b, c):
        """
        :type arr: List[int]
        :type a: int
        :type b: int
        :type c: int
        :rtype: int
        """
        count = 0
        for i in range(len(arr)-2):
            for j in range(i+1,len(arr)-1):
                if abs(arr[i] - arr[j]) <= a:
                    for k in range(j+1,len(arr)):
                        if abs(arr[j] - arr[k]) <= b and abs(arr[i] - arr[k]) <= c:
                            count += 1
                    
        return (count)