704. 二分查找(leetcode)

https://leetcode.cn/problems/binary-search/

简单二分

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int l=0,r=nums.size()-1;
        while(l<r)
        {
            int mid=l+r>>1;
            if(nums[mid]>=target)r=mid;
            else l=mid+1;
        }
        if(nums[l]!=target)return -1;
        return l;
    }
};