题目：
Suppose a sorted array is rotated at some pivot unknown to you beforehand.
(i.e., 0 1 2 4 5 6 7 might become 4
5 6 7 0 1 2).
Find the minimum element.
You may assume no duplicate exists in the array.
我的解法：（1）算法思想：
记low=0，high=num.size()-1，用二分法：当num[mid]>num[high]时，low=mid+1；否则，high=mid。直到low=high，返回num[low]即可。
（2）代码如下：
Find Minimum in Rotated Sorted Array
原文：http://blog.csdn.net/littlebob180/article/details/43273275