# [Solution] Count Good Triplets in an Array solution leetcode

Count Good Triplets in an Array  – You are given two 0-indexed arrays `nums1` and `nums2` of length `n`, both of which are permutations of `[0, 1, ..., n - 1]`.

good triplet is a set of `3` distinct values which are present in increasing order by position both in `nums1` and `nums2`. In other words, if we consider `pos1v` as the index of the value `v` in `nums1` and `pos2v` as the index of the value `v` in `nums2`, then a good triplet will be a set `(x, y, z)` where `0 <= x, y, z <= n - 1`, such that `pos1x < pos1y < pos1z` and `pos2x < pos2y < pos2z`.

Return the total number of good triplets.

# Count Good Triplets in an Array solution leetcode

```Input: nums1 = [2,0,1,3], nums2 = [0,1,2,3]
Output: 1
Explanation:
There are 4 triplets (x,y,z) such that pos1x < pos1y < pos1z. They are (2,0,1), (2,0,3), (2,1,3), and (0,1,3).
Out of those triplets, only the triplet (0,1,3) satisfies pos2x < pos2y < pos2z. Hence, there is only 1 good triplet.
```

## Count Good Triplets in an Array solution leetcode

```Input: nums1 = [4,0,1,3,2], nums2 = [4,1,0,2,3]
Output: 4
Explanation: The 4 good triplets are (4,0,3), (4,0,2), (4,1,3), and (4,1,2).
```

### Count Good Triplets in an Array solution leetcode

• `n == nums1.length == nums2.length`
• `3 <= n <= 105`
• `0 <= nums1[i], nums2[i] <= n - 1`
• `nums1` and `nums2` are permutations of `[0, 1, ..., n - 1]`.