Submission #1129910

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129910		pedreitorzelda	Combo (IOI18_combo)	C++20	Compilation error	0 ms	0 KiB

combo

string guess_sequence(int N){
    string ans = "";
    vector<char>possible = {'A','B','X','Y'};
    vector<char>npossible = {'A','B','X','Y'};
    for(int i=0;i<N;i++){
        if(i==N-1){
            string q = "";
            q+=ans+npossible[0];
            q+=ans+npossible[1];
            int tmp = press(q);
            if(tmp==N){
                q=ans+npossible[0];
                tmp = press(q);
                if(tmp==N)ans+=npossible[0];
                else ans+=npossible[1];
            }else{
                if(npossible.size()==3)ans+=npossible[2];
                else{
                    q=ans+npossible[2];
                    tmp = press(q);
                    if(tmp==N)ans+=npossible[2];
                    else ans+=npossible[3];
                }
            }
        }else if(i==0){
            string q = "";
            q+=possible[0]+possible[1];
            int tmp = press(q);
            if(tmp==1){
                q = possible[0];
                tmp = press(q);
                if(tmp==1)ans+=possible[0];
                else ans+=possible[1];
            }else{
                q = possible[2];
                tmp = press(q);
                if(tmp==1)ans+=possible[2];
                else ans+=possible[3];
            }npossible.clear();
            for(int j=0;j<4;j++){
                if(possible[j]!=ans[0])npossible.push_back(possible[j]);
            }
        }else{
            string q = "";
            q+=ans+npossible[0];
            for(int j=0;j<3;j++){
                q+=ans+npossible[1]+npossible[j];
            }int tmp = press(q);
            if(tmp==1){
                ans+=npossible[0];
            }else if(tmp==2){
                ans+=npossible[1];
            }else{
                ans+=npossible[2];
            }
        }
    }
    return ans;
}

Compilation message (stderr)

combo.cpp:1:1: error: 'string' does not name a type
    1 | string guess_sequence(int N){
      | ^~~~~~