153. Find Minimum in Rotated Sorted Array

153. 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.

You may assume no duplicate exists in the array.

思路：如果nums[mid]<nums[high]，说明后半部分是顺序的，且最小值在[start ... mid]之间。否则，说明有反转，最小值在后半区间。

<span style="font-size:18px;">class Solution {
int binary_search(vector<int> & nums, int s, int e)
{
if(nums[s]<=nums[e])
return nums[s];
int mid=s+(e-s)/2;
if(nums[mid]>nums[e]) return binary_search(nums,mid+1,e);
else return binary_search(nums,s,mid);
}
public:
int findMin(vector<int>& nums) {
int n=nums.size();
return binary_search(nums,0,n-1);
}
};</span>