http://www.lintcode.com/en/problem/find-minimum-in-rotated-sorted-array/

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.

Example Given [4, 5, 6, 7, 0, 1, 2] return 0

解题：反转数组里面找最小值，我们只需要判断取中间值的时候左半边是sorted还是右半边是sorted。方法就是拿mid值和最后一个值比。

public class Solution {
    /**
     * @param nums: a rotated sorted array
     * @return: the minimum number in the array
     */
    public int findMin(int[] nums) {
        // write your code here
        if (nums == null || nums.length == 0) {
            return -1;
        }
        int start = 0;
        int end = nums.length - 1;
        int target = nums[end];
        while (start + 1 < end) {
            int mid = start + (end - start) / 2;
            if (nums[mid] <= target) {
                end = mid;
            } else {
                start = mid;
            }

        }
        if (nums[start] < nums[end]) {
            return nums[start];
        }
        return nums[end];
    }
}