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# 0611. Valid Triangle Number

<https://leetcode.com/problems/valid-triangle-number>

## Description

Given an integer array `nums`, return *the number of triplets chosen from the array that can make triangles if we take them as side lengths of a triangle*.

**Example 1:**

```
**Input:** nums = [2,2,3,4]
**Output:** 3
**Explanation:** Valid combinations are: 
2,3,4 (using the first 2)
2,3,4 (using the second 2)
2,2,3
```

**Example 2:**

```
**Input:** nums = [4,2,3,4]
**Output:** 4
```

**Constraints:**

* `1 <= nums.length <= 1000`
* `0 <= nums[i] <= 1000`

## ac

```java
```