Submission #1215025

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215025		mariamp1	Combo (IOI18_combo)	C++20	100 / 100	8 ms	488 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>
using namespace std;

string guess_sequence(int N){
    string s = "";
    string p = "";

    char first;
    if (press("AB")) {
        if (press("A")) first = 'A';
        else first = 'B';
    } else {
        if (press("X")) first = 'X';
        else first = 'Y';
    }
    s += first;
    if (N == 1) return s;
    vector<char> letters;
    for (char c : {'A', 'B', 'X', 'Y'}) {
        if (c != first) letters.push_back(c);
    }
    for (int i = 1; i < N - 1; i++) {
        p = "";
        p += s + letters[0];
        for (char c : letters) {
            p += s + letters[1] + c;
        }
        int coins = press(p);
        if (coins == (int)s.size()) {
            s += letters[2];
        } else if (coins == (int)s.size() + 1) {
            s += letters[0];
        } else {
            s += letters[1];
        }
    }
    char last;
    if (press(s + "A" + s + "B") == (int)s.size() + 1) {
        if (press(s + "A") == (int)s.size() + 1) last = 'A';
        else last = 'B';
    } else {
        if (press(s + "X") == (int)s.size() + 1) last = 'X';
        else last = 'Y';
    }
    s += last;
    return s;
}

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