https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/description/
Suppose an array sorted in ascending order 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.
注意，我们要找的最小值，只会在右端，所以如果已经在右端，则挪RIGHT
如果在左（通过和 NUMS[RIGHT] 比较），则挪LEFT 往右端的深沟走
time: o(logn) worst o(n)
space: o(1)
1 public int findMin(int[] nums) {
2 if (nums ==null || nums.length ==0) return -1 ;
3 int left = 0, right = nums.length -1 ;
4 while(left + 1 < right){
5 int mid = left + (right - left)/2 ;
6 if (nums[left] == nums[mid]) {
7 left++;
8 }
9 if (nums[right] == nums[mid]) {
10 right--;
11 }
12 //the lower part
13 if (nums[mid]<nums[right]) {
14 right = mid;
15 }
16 //the upper part
17 else if(nums[mid]>nums[right]){
18 left = mid ;
19 }
20 }
21 //post processing
22 return Math.min(nums[left], nums[right]);
23 }
注意针对 rotated sorted array 去重复的固定套路
参考 33,81,153, 154