leetcode 976
To the array by a number of positive (representative length) of a given composition A
, wherein the three returned by the maximum perimeter length of the composition, the area of the triangle is not zero.
If not form any non-zero area triangles return 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 source
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 }