Submission #1051898

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051898		matere	Colors (BOI20_colors)	C++14	9 / 100	1 ms	512 KiB

Colors

#include<bits/stdc++.h>
using namespace std;
int main(){
    long long n,resp;
    cin>>n;
    if(n<=64){
        int cur=1;
        cout<<"? "<<1<<endl;
        cin>>resp;
        for(int i=0;i<n/2;i++){
            cur=n-cur+1;
            cout<<"? "<<cur<<endl;
            cin>>resp;
            if(resp==0){
                cout<<"= "<<n-i*2<<endl;
                return 0;
            }
            if(i==n/2-1 and n%2!=1){
                cout<<"= "<<1<<endl;
                return 0;
            }
            cur=n-cur+2;
            cout<<"? "<<cur<<endl;
            cin>>resp;
            if(resp==0){
                cout<<"= "<<n-i*2-1<<endl;
                return 0;
            }
        }
        cout<<"= "<<1<<endl;
        return 0;
    }
    long long l=1,r=n;
    long long centr=(n+1)/2;
    while(l+l%2+2<r-r%2){
        long long mid=(l+r)/2;
        if(mid%2==1) mid--;
        cout<<"? "<<centr-mid/2<<endl;
        cin>>resp;
        cout<<"? "<<centr+mid/2<<endl;
        cin>>resp;
        if(resp==1){
            r=mid;
        }
        else{
            l=mid+1;
        }
    }
    // cout<<l<<' '<<r<<endl;
    long long r1,r2,r3,r4;
    cout<<"? "<<centr+(l+3)/2<<endl;
    cin>>r1;
    cout<<"? "<<centr-(l+3)/2<<endl;
    cin>>r2;
    cout<<"? "<<centr+(l+1)/2<<endl;
    cin>>r3;
    cout<<"? "<<centr-(l+1)/2<<endl;
    cin>>r4;
    if(r2==0) cout<<"= "<<r<<endl;
    else if(r3==0) cout<<"= "<<r-1<<endl;
    else if(r4==0) cout<<"= "<<r-2<<endl;
    else cout<<"= "<<r-3<<endl;
}

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