[Leetcode]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.

比较简单，只是旋转了一次，我们也用二分查找。和最右边的值作比较，比最右边的值大，说明在mid右边，所以left = mid +1;

比右边值小，说明在mid左边，所以right=mid-1

 

class Solution {
public:
    int findMin(vector<int> &num) {
        int left=0,right = num.size()-1;
        while(left<=right){
            int mid=(right+left)/2;
            if(num[mid]>num[num.size()-1])
                left = mid + 1;
            else
                right = mid -1;
        }
        return num[left];
    }
};