Acwing 22

class Solution {
public:
    int func(vector<int>& nums,int begin,int end){
        while(begin + 1 < end){
            int mid = begin + ((end - begin) >>1);
            if(nums[mid] == nums[begin] && nums[mid] == nums[end]){
                int min = nums[begin];
                for(int i = begin;i<=end;i++){
                    if(min > nums[i]) min = nums[i];
                }
                return min;
            }
            if(nums[mid] >= nums[begin]) //左侧有序
                begin = mid;
            else
                end = mid;
        }
        return nums[end];
    }
    int findMin(vector<int>& nums) {
        int begin = 0;
        int end = nums.size()-1;
        if(nums.size() == 0) return -1;
        if(nums[begin] < nums[end]) return nums[begin];//考虑没有旋转的情况
        int res = func(nums,begin,end);
        return res;
    }
};