二分法（算法）

https://blog.csdn.net/qq_36102055/article/details/104375766

https://www.acwing.com/solution/content/107848/

https://www.acwing.com/problem/content/791/

#include <iostream>
#include <cstdio>
using namespace std;
// 查找左边界
int Search_Left(int l, int r)
{
    while (l < r)
    {
        int mid = (l + r) >> 1;
        if (check(mid))
            r = mid;
        else
            l = mid + 1;
    }
    return l;
}
//查找右边界
int Right_Search(int l,int r){
    while(l<r) {
        int mid = (l + r + 1) >> 1;
        if(check(mid)) l = mid;
        else r = mid - 1;
    }
    return l;
}
int main(void)
{
}