Submission #749948

#	Time	Username	Problem	Language	Result	Execution time	Memory
749948		vjudge1	Carnival (CEOI14_carnival)	C++17	0 / 100	0 ms	208 KiB

carnival

#include<bits/stdc++.h>
using namespace std;
int ask(int l, int r) {
	if(l>=r) return -1;
	cout<<"? "<<l<<" "<<r<<endl;
	int x;
	cin>>x;
	return x;
}
signed main() {
//	ios_base::sync_with_stdio(0);
//	cin.tie(0);
	int n;
	cin>>n;
	int smax=ask(1,n);
	int l,r;
	if(smax==n||ask(1,smax)==smax) {
		l=1; r=smax;
		while(l<r-1) {
			int m=(l+r)/2;
			if(ask(m,smax)==smax) {
				l=m;
			}
			else r=m;
		}
		cout<<"! "<<l<<endl;
	}
	else {
		l=smax, r=n;
		while(l<r-1) {
			int m=(l+r)/2;
			if(ask(smax,m)==smax) {
				r=m;
			}
			else l=m;
		}
		cout<<"! "<<r<<endl;
	}
}

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20