leetcode之 Minimum Height Trees

题目：

Given an array of n positive integers and a positive integer s, find the minimal length of a subarray of which the sum ≥ s. If there isn't one, return
0 instead.

For example, given the array 

[2,3,1,2,4,3]

 and 

s
= 7

,

the subarray 

[4,3]

 has the minimal length under the problem constraint.

解答：

很简单的两个指针就完事，时间比较紧张，以后一眼瞅出来怎么做的都不写代码了