제출 #392904

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
392904		wind_reaper	Colors (BOI20_colors)	C++17	0 / 100	1 ms	200 KiB

Colors

#include <bits/stdc++.h>

using namespace std;

int Ask(int64_t num){
	cout << "? " << num << endl;
	int x;
	cin >> x;
	return x; 
}

int32_t main(){
	ios_base::sync_with_stdio(false); 
	cin.tie(NULL); 
	
	int64_t n;
	cin >> n;

	int64_t l = 1, r = n-1, start = n, cur = 0, dir = 1;
	while(l <= r){
		int64_t mid = (l + r) >> 1;
		cur += dir*mid;
		dir *= -1;
		start = min(start, n - cur);
		l = mid + 1;
	}

	l = 1, r = n-1, dir = 1;

	int64_t answer = n-1;

	Ask(start);

	while(l <= r){
		int64_t mid = (l + r) >> 1;
		int64_t ask = start + dir*mid;
		dir *= -1;
		if(Ask(ask)){
			answer = mid;
			r = mid - 1;
		}
		else l = mid + 1;
		start = ask;
	}

	cout << "= " << answer << '\n';
	return 0; 
}

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