Submission #1215999

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215999		lizi14	Combo (IOI18_combo)	C++20	97 / 100	8 ms	468 KiB

combo

#include "combo.h"

using namespace std;

string guess_sequence(int N) {
    int d[4]={0,0,0,0};
    char p[4]={'A','B','X','Y'};
    string s_1,s_2,s_3,s_4;
    string sa="";
    int coins = press("AB");
    if(coins>=1){
        coins=press("A");
        if(coins==1){
            d[0]=1;
            sa="A";
        }
        else{
            d[1]=1;
            sa+="B";
        }
    }
    else{
        coins=press("X");
        if(coins==1){
            d[2]=1;
            sa+="X";
        }
        else{
            d[3]=1;
            sa+="Y";
        }
    }
    if(N==1){
      return sa;
    }
    if(d[3]==1){
        s_1="A";
        s_2="BA";
        s_3="BB";
        s_4="BX";
    }
    else if(d[2]==1){
        s_1="A";
        s_2="BA";
        s_3="BB";
        s_4="BY";
    }
    else if(d[0]==1){
        s_1="X";
        s_2="YY";
        s_3="YX";
        s_4="YB";
    }
    else{
        s_1="A";
        s_2="XA";
        s_3="XX";
        s_4="XY";
    }
    while(sa.size()<N-1){
        string w="";
        for(int i=1; i<=4; i++){
            w+=sa;
            if(i%4==1){
                w+=s_1;
            }
            else if(i%4==2){
                w+=s_2;
            }
            else if(i%4==3){
                w+=s_3;
            }
            else w+=s_4;
        }
        coins=press(w);
        
        if(coins==sa.size()){
            sa+=s_4[1];
        }
        else if(coins==sa.size()+1){
            sa+=s_1[0];
            
        }
        else sa+=s_2[0];
    }
    int k=0;
    for(int i=0; i<3; i++){
        if(d[i]==0){
            string w=sa;
            w+=p[i];
            coins=press(w);
           
            if(coins==N){
                sa+=p[i];
                return sa;
            }
            else d[i]=1; 
            k++;
        }
    }
    sa+=p[3];
    return sa;

}

• Subtask 1: 5 / 5
• Subtask 2: 92 / 95