###### tags: `Array`, `Math`, `Greedy`, `Sorting`

# LeetCode 976.Largest Perimeter Triangle

Given an integer array ```nums```, return the largest perimeter of a triangle with a non-zero area, formed from three of these lengths. If it is impossible to form any triangle of a non-zero area, return ```0```.

>Example 1:

Input: nums = [2,1,2]
Output: 5
Explanation: You can form a triangle with three side lengths: 1, 2, and 2.

>Example 2:

Input: nums = [1,2,1,10]
Output: 0
Explanation: 
You cannot use the side lengths 1, 1, and 2 to form a triangle.
You cannot use the side lengths 1, 1, and 10 to form a triangle.
You cannot use the side lengths 1, 2, and 10 to form a triangle.
As we cannot use any three side lengths to form a triangle of non-zero area, we return 0.

### Constraints:

- $3 <= nums.length <= 10^4$
- $1 <= nums[i] <= 10^6$
---
### Idea:
>
### Solution:

Python:

class Solution:
    def largestPerimeter(self, nums: List[int]) -> int:
        nums.sort()
        print(nums)
        for i in range(len(nums)-1,1,-1):
            if nums[i] < nums[i-1] + nums[i-2]:
                return nums[i] + nums[i-1]+ nums[i-2]
        return 0
        

C++: