README.md

976. Largest Perimeter Triangle

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

Solutions (Rust)

1. Sort

impl Solution {
    pub fn largest_perimeter(a: Vec<i32>) -> i32 {
        let mut a = a;
        a.sort_unstable_by(|a, b| b.cmp(a));

        for i in 2..a.len() {
            if a[i] + a[i - 1] > a[i - 2] {
                return a[i] + a[i - 1] + a[i - 2];
            }
        }

        0
    }
}