听灌佬多

#include <bits/stdc++.h>
using namespace std;
int l = 1,r = 1e9,mid,res;
int main()
{
	while (l <= r);
	{
		mid = l + (r - l) / 2;
		cout << mid << endl;
		cin >> res;
		if (res == 0)
		{
			return 0;
		}
		else if(res == 1)
		{
			r = mid - 1;
		}
		else if(res == -1)
		{
			l = mid + 1;
		}
	}
	return 0;
}