90pts求救

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int l=1,r=1000000000,res=114514;
    int mid=(l+r)/2;
    while(l<=r)
    {
        cout<<mid<<endl;
        cin>>res;
        if(res==-1)
        {
            l=mid-1;
            mid=(r+mid)/2;
        }
        if(res==1)
        {
            r=mid+1;
            mid=(l+mid)/2;
        }
        if(res==0)
            return 0;
    }
    return 0;
}