Submission #1180110

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Source Code Expand

//in the name of allah
#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
bool ans[N];
bool ask(int v , int u){
        cout << "? " << v << " " << u << endl;        
        fflush(stdout);
        char ans;
        cin >> ans;
        return (ans == 'Y');
}

int main(){
        int n , m;
        cin >> n >> m;
        if(n<=m){
                cout << "Impossible\n";
                return 0;
        }
        stack<int> st;
        for(int i=0 ; i<n+m ; i++){                
                if(!st.size()){
                        st.push(i);
                        continue;
                }              
                if(ask(i , st.top())){
                        if(ask(st.top() , i))
                                st.push(i);                      
                }else
                        st.pop();
        }
        int v = st.top();
        for(int i=0 ; i<n+m ; i++)
                ans[i] = ask(v , i);
        cout << "! ";
        for(int i=0 ; i<n+m ; i++)
                cout << ans[i];
        cout << endl;
        fflush(stdout);
}

Submission Info

Judge Result