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：如果中间节点的值最大，则取后半部分，如果中间节点的值最小，则取前半部分。

C++实现代码如下：（采用二分法的方法，注意边界的处理）

#include<iostream>

#include<vector>

using namespace std;



class Solution

{

public:

    int findMin(vector<int> &num)

    {

        if(num.empty())

            return 0;

        int s=0;

        int t=num.size()-1;

        if(num[s]<num[t])

            return num[s];

        while(s<t)

        {

            int mid=(s+t)/2;

            if(num[mid]<num[t])

                t=mid;

            else

                s=mid+1;

        }

        return num[s];

    }

};



int main()

{

    Solution s;

    vector<int> num={4,5,6,7,8,9,0,1,2,3};

    cout<<s.findMin(num)<<endl;

}