2475. Number of Unequal Triplets in Array
Easy
292
25

You are given a 0-indexed array of positive integers `nums`. Find the number of triplets `(i, j, k)` that meet the following conditions:

• `0 <= i < j < k < nums.length`
• `nums[i]`, `nums[j]`, and `nums[k]` are pairwise distinct.
• In other words, `nums[i] != nums[j]`, `nums[i] != nums[k]`, and `nums[j] != nums[k]`.

Return the number of triplets that meet the conditions.

Example 1:

```Input: nums = [4,4,2,4,3]
Output: 3
Explanation: The following triplets meet the conditions:
- (0, 2, 4) because 4 != 2 != 3
- (1, 2, 4) because 4 != 2 != 3
- (2, 3, 4) because 2 != 4 != 3
Since there are 3 triplets, we return 3.
Note that (2, 0, 4) is not a valid triplet because 2 > 0.
```

Example 2:

```Input: nums = [1,1,1,1,1]
Output: 0
Explanation: No triplets meet the conditions so we return 0.
```

Constraints:

• `3 <= nums.length <= 100`
• `1 <= nums[i] <= 1000`
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