[LeetCode] Problem 976 - Largest Perimeter Triangle

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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

No.1

Input: [2,1,2]

Output: 5

No.2

Input: [1,2,1]

Output: 0

No.3

Input: [3,2,3,4]

Output: 10

No.4

Input: [3,6,2,3]

Output: 8

Note

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

Code

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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;
}