y总二分写法

class Solution {
public:
    int findMin(vector<int>& a) {
        int len = a.size();
        if(len == 0) return -1;
        if(a[0] < a[len -1]) return a[0];
        while(a[len - 1] >= a[len - 2] && len >= 1) len --;
        int l = 0 , r = len - 1;
        while(l < r) {
            int mid = l + r >> 1;
            if(a[mid] >= a[0]) l = mid + 1;
            else r = mid ;
        }
        return a[r];
    }
};

sort 一下也能过

class Solution {
public:
    int findMin(vector<int>& nums) {
        sort(nums.begin() , nums.end());
        if(nums.size() == 0) return -1;
        return nums[0];
    }
};