Problem

Given an array A of positive lengths, return the largest perimeter of a triangle with non-zero area, formed from 3 of these lengths.

If it is impossible to form any triangle of non-zero area, return 0.

Note:

• 3 <= A.length <= 10000
• 1 <= A[i] <= 10^6

Example1

Input: [2,1,2]
Output: 5

Example2

Input: [1,2,1]
Output: 0

Example3

Input: [3,2,3,4]
Output: 10

Example4

Input: [3,6,2,3]
Output: 8

Solution

class Solution {
public:
    int largestPerimeter(vector<int>& A) {
        sort(A.begin(),A.end());
        
        for(int i = A.size()-1;i>=2;--i)
        {
            if(A[i-2] + A[i-1] > A[i])
                return A[i] + A[i-1] + A[i-2];
        }

        return 0;

        

    }
};