Submission #1364699

#	Time	Username	Problem	Language	Result	Execution time	Memory
1364699		hsuan._.0528	Dark Ride (EGOI25_darkride)	C++20	100 / 100	1 ms	560 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define LL long long
#define pii pair<int, LL>
#define F first
#define S second
const int maxn = 3e5+10;
const int mod = 998244353;
const LL inf = 1e9;

int n, A=0, B=0;

int qq(string s){
    cout<<"? "<<s<<endl;
    int a;
    cin>>a;
    return a;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin>>n;
    int x=0, b=0;
    for(int i=0; i<15; i++){
        string s(n, '0');
        for(int j=0; j<n; j++)
            if((1<<i)&j)  s[j]='1';
        if(qq(s)%2)  x^=(1<<i), b=i;
    }
    vector<int> v;
    for(int j=0; j<n; j++){
        if((1<<b)&j)
            v.push_back(j);
    }
    int l=0, r=v.size()-1, m;
    while(l<=r){
        m=(l+r)/2;
        string s(n, '0');
        for(int j=0; j<=m; j++)  s[v[j]]='1';
        if(qq(s) % 2)  r=m-1;
        else l=m+1;
    }
    A=v[l];
    cout<<"! "<<A<<" "<<(A^x)<<endl;
    return 0;
}

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 15 / 15
• Subtask 4: 17 / 17
• Subtask 5: 16 / 16
• Subtask 6: 14 / 14
• Subtask 7: 29 / 29