标签：example line rev merge HERE imp reverse less order
leetcode 976
给定由一些正数（代表长度）组成的数组 A，返回由其中三个长度组成的、面积不为零的三角形的最大周长。
如果不能形成任何面积不为零的三角形，返回 0。
1 impl Solution { 2 pub fn largest_perimeter(a: Vec<i32>) -> i32 { 3 let mut a = a; 4 a.sort_by(|a, b| b.cmp(&a)); 5 for i in 0..a.len()-2 { 6 if a[i] < a[i+1] + a [i+2] { 7 return a[i] + a[i+1] + a[i+2]; 8 } 9 } 10 0 11 } 12 }
sort_by源码
1 /// # Examples 2 /// 3 /// ``` 4 /// let mut v = [5, 4, 1, 3, 2]; 5 /// v.sort_by(|a, b| a.cmp(b)); 6 /// assert!(v == [1, 2, 3, 4, 5]); 7 /// 8 /// // reverse sorting 9 /// v.sort_by(|a, b| b.cmp(a)); 10 /// assert!(v == [5, 4, 3, 2, 1]); 11 /// ``` 12 #[stable(feature = "rust1", since = "1.0.0")] 13 #[inline] 14 pub fn sort_by<F>(&mut self, mut compare: F) 15 where F: FnMut(&T, &T) -> Ordering 16 { 17 merge_sort(self, |a, b| compare(a, b) == Less); 18 }
标签：example line rev merge HERE imp reverse less order
原文地址：https://www.cnblogs.com/chenguifeng/p/12215189.html
