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`