제출 #951627

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
951627		koukirocks	Colors (BOI20_colors)	C++17	100 / 100	2 ms	756 KiB

Colors

#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
 
using namespace std;
typedef long long ll;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
const ll MAX=3e5+10,P=1e9+7;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;

ll n;

ll begin() {
	vector<ll> cross;
	ll l=1,r=n-1;
	while (l<=r) {
		ll mid=(l+r)/2;
		cross.push_back(mid);
		l=mid+1;
	}
	reverse(all(cross));
	ll now=1;
	for (int i=0;i<cross.size();i++) {
		now+=((i&1)?-1:1)*cross[i];
	}
	return now;
}

int query(ll q) {
	cout<<"? "<<q<<"\n"<<flush;
	int x;
	cin>>x;
	return x;
}

int main() {
	speed;
	cin>>n;
	ll now=begin();
	ll l=1,r=n-1;
	ll cnt=(now<=n/2);
	query(now);
	ll ans=n;
	while (l<=r) {
		ll mid=(l+r)>>1;
		now+=((cnt&1)?1:-1)*mid;
		cnt^=1;
		int x=query(now);
		if (x==0) l=mid+1;
		else {
			ans=mid;
			r=mid-1;
		}
	}
	cout<<"= "<<ans<<"\n"<<flush;
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

Colors.cpp: In function 'll begin()':
Colors.cpp:29:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |  for (int i=0;i<cross.size();i++) {
      |               ~^~~~~~~~~~~~~

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