Submission #861697

#	Time	Username	Problem	Language	Result	Execution time	Memory
861697		Ariadna	Combo (IOI18_combo)	C++14	100 / 100	15 ms	1980 KiB

combo

#include <bits/stdc++.h>
 
using namespace std;
 
int press(string p);
 
vector < char > aux;
 
string first_char() {
    string s = "AB";
    if (press(s)) {
        s = "A";
        if (press(s)) {
            aux = {'B', 'X', 'Y'};
            return s;
        }
        aux = {'A', 'X', 'Y'};
        return "B";
    }
    s = "X";
    if (press(s)) {
        aux = {'A', 'B', 'Y'};
        return s;
    }
    aux = {'A', 'B', 'X'};
    return "Y";
}
 
string guess_sequence(int N) {
    string s = first_char();
    for (int i = 2; i < N; ++i) {
        string q = s + aux[0] + aux[0] + s + aux[0] + aux[1] + s + aux[0] + aux[2] + s + aux[1];
        int ans = press(q);
        if (ans == i + 1) s += aux[0];
        else if (ans == i) s += aux[1];
        else s += aux[2];
    }
    
    if (N > 1) {
        s += aux[0];
        if (press(s) == N) return s;
        s[N - 1] = aux[1];
        if (press(s) == N) return s;
        s[N - 1] = aux[2];
        return s;
    }
    return s;
}

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