Submission #1021378

#	Time	Username	Problem	Language	Result	Execution time	Memory
1021378		Aisha	Combo (IOI18_combo)	C++17	100 / 100	31 ms	2196 KiB

combo

#include "combo.h"

#include <bits/stdc++.h>

using namespace std;

std::string guess_sequence(int N) {
    string s = "";
    string p = "AB";
    int coins = press(p);
    if (coins == 2) s = p;
    else if (coins == 1) {
        p = "A";
        coins = press(p);
        if (coins == 1) s = "A";
        else s = "B";
    } else {
        p = "X";
        coins = press(p);
        if (coins == 1) s = "X";
        else s = "Y";
    }

    string A = "ABXY";
    string a = "";

    for (char c : A) {
        if (s[0] != c) a = a + c;
    }

    coins = 1;
    int sz = s.size();
    while (sz < N - 1) {
        p = "";
        for (int i = 0; i < 4; i++) {
            p = p + s;
            if (i < 3) {
                p = p + a[0];
                p = p + a[i];
            } else p = p + a[1];
        }
    
        int k = press(p) - s.size();
        if (k == 2) {
            s += a[0];
        } else if (k == 1) {
            s += a[1];
        } else {
            s += a[2];
        }

        sz = s.size();
    }
    
    if (sz == N) {
        return s;
    }
    
    p = s;
    p += a[0];
    p += s;
    p += a[1];
    int k = press(p) - s.size();
    
    if (k == 1) {
        p = s;
        p += a[0];
        if (press(p) - s.size() == 1) {
            s += a[0];
        } else s += a[1];
    } else s += a[2];

    return s;
}

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