Submission #636504

#	Time	Username	Problem	Language	Result	Execution time	Memory
636504		tvladm2009	Guess the number (BOI20_guess)	C++14	100 / 100	1 ms	256 KiB

Guess

#include <iostream>

using namespace std;

int n, res = 0;

void ask(int x) {
    cout << "? " << x << "\n";
    cout.flush();
    cin >> res;
}

int cb() {
    int l = 1, r = n, sol = -1;
    while (l <= r) {
        int mid = (l + r) / 2;
        ask(mid);
        if (res == 0) {
            sol = mid;
            break;
        } else if (res == 1) {
            r = mid - 1;
        } else {
            l = mid + 1;
        }
    }
    return sol;
}

int main() {
    cin >> n;
    int answer = cb();
    cout << "= " << answer;
    return 0;
}

• Subtask 1: 29 / 29
• Subtask 2: 71 / 71