Leetcode 976. Largest Perimeter Triangle

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/M_sdn/article/details/86413116

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.

Example 1:

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

Example 2:

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

Example 3:

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

Example 4:

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

Note:

1. 3 <= A.length <= 10000
2. 1 <= A[i] <= 10^6

    public int largestPerimeter(int[] A) {
        Arrays.sort(A);
        for (int i = A.length-1; i >= 2; i--) {
            if (A[i-2] + A[i-1] > A[i]) {
                return A[i-2] + A[i-1] + A[i];
            }
        }
        return 0;
    }