153. Find Minimum in Rotated Sorted Array

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.

链接： http://leetcode.com/problems/find-minimum-in-rotated-sorted-array/

6/13/2017

注意：

会有mid就是最小值的情况，所以更新hi的时候要把mid位置包括进去。实际上lo = mid + 1是没有问题的，因为是nums[mid]比nums[hi]大，所以它肯定不是最小值。

找最小点比找一个特定的值容易很多。

 1 public class Solution {
 2     public int findMin(int[] nums) {
 3         if (nums == null || nums.length == 0) {
 4             return -1;
 5         }
 6         int lo = 0, hi = nums.length - 1;
 7         while (lo + 1 < hi) {
 8             int mid = lo + (hi - lo) / 2;
 9             if (nums[mid] < nums[hi]) {
10                 hi = mid;
11             } else {
12                 lo = mid;
13             }
14         }
15         if (nums[lo] < nums[hi]) {
16             return nums[lo];
17         }
18         return nums[hi];
19     }
20 }