Submission #484709

#	Time	Username	Problem	Language	Result	Execution time	Memory
484709		ac2hu	Colors (BOI20_colors)	C++14	0 / 100	1 ms	200 KiB

Colors

#include <bits/stdc++.h>
using namespace std;
#define ll long long
map<ll,bool> used;
ll n;
bool good(ll mid, ll &cur){
	if(cur + mid <= n && !used[cur + mid]){
		cur += mid;
		used[cur] = true;
		cout << "? " << cur << endl;
		bool a;cin >> a;
		return a;
	}
	else if(cur - mid > 0 && !used[cur - mid]){
		cur -= mid;
		used[cur] = true;
		cout << "? " << cur << endl;
		bool a;cin >> a;
		return a;
	}
	cout << "= " << 1e9 << endl;
	return false;
}
signed main(){
	cin >> n;
	ll cur = 0;
	good(1,cur);
	ll l = 1,r = n;
	while(l < r){
		ll mid = (l + r)/2;
		if(good(mid,cur)){
			r = mid;
		}
		else{
			l = mid + 1;
		}
	}
	cout << "= "<< l << endl;
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 13
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 33