Description
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.
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。
题目链接：https://leetcode.com/problems/largest-perimeter-triangle/
Difficulty: easy
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:
- 3 <= A.length <= 10000
- 1 <= A[i] <= 10^6
分析
- updating（Solution）
参考代码
class Solution(object):
def largestPerimeter(self, A):
A.sort()
for i in xrange(len(A) - 3, -1, -1):
if A[i] + A[i+1] > A[i+2]:
return A[i] + A[i+1] + A[i+2]
return 0