Willy is wandering in NZ

*大多数朋友如果找到这篇文章，就是来看解答的，所以完整的题目放到文章的最后了。思路：1、首先根据题目，大家第一反应就是无脑嵌套遍历所有情况，这样的时间复杂度是O(n^2+n)/2，远远超出O(n)的题目里的要求。2、其次就是找规律了，这个slice一定发生在最小值周围吗？不一定！比如[-1, -1, 12, -9, 10]。所以不用去思考先找到最小值，再向两边递归的思路了。

Thinking:1. Look every circle as a range, that will help us think in a simpler way. So the first step is translate circles into ranges(from "center&radius" to range):A[0]=1    >>    [-1,1]A[1]=5

Thinking:This lesson is about two kinds of data structures -- queue and stack. After reading the question carefully, you can tell stack is a good choice. As it's a EASY-level question, there is neit