Submission #541611

#	Time	Username	Problem	Language	Result	Execution time	Memory
541611		sidon	Colors (BOI20_colors)	C++17	100 / 100	2 ms	336 KiB

Colors

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

bool query(ll i) {
	cout << "? " << i << endl;
	cin >> i;
	return i;
}

int main() {
	ll N; cin >> N;

	ll i = 0, c = 0, l = 1, r = N, d = -1;

	for(; l < r; d = -d) {
		l = (l + r - 1) >> 1;
		i = max(i, ll(1) - (c += d * l++));
	}

	query(i);
	l = 1, r = N, d = -1;
	for(; l < r; d = -d) {
		ll m = (l + r - 1) >> 1;
		if(query(i += d * m)) r = m;
		else l = m + 1;
	}
	cout << "= " << l << endl;
}

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 24 / 24
• Subtask 5: 33 / 33