Submission #750222

#	Time	Username	Problem	Language	Result	Execution time	Memory
750222		cheat_when_I_was_young	Combo (IOI18_combo)	C++17	100 / 100	35 ms	572 KiB

combo

#include<bits/stdc++.h>
#include "combo.h"
using namespace std;
string guess_sequence(int n) {
    int coins;
    vector<char> c = {'A', 'B', 'X', 'Y'};
    string ans = "";
    coins = press(ans + "A" + ans + "B");
    if (coins - ans.size()) {
        coins = press(ans + "A");
        if (coins - ans.size()) ans += "A";
        else ans += "B";
    } else {
        coins = press(ans + "X");
        if (coins - ans.size()) ans += "X";
        else ans += "Y";
    }
    vector<string> d, e;
    if (ans == "A") {
        d = {"B", "XB", "XX", "XY"};
        e = {"Y", "B", "X"};
    } else if (ans == "B") {
        d = {"A", "XA", "XX", "XY"};
        e = {"Y", "A", "X"};
    } else if (ans == "X") {
        d = {"A", "YA", "YB", "YY"};
        e = {"B", "A", "Y"};
    } else {
        d = {"A", "XA", "XB", "XX"};
        e = {"B", "A", "X"};
    }
    while ((int)ans.size() < n-1) {
        coins = press(ans + d[0] + ans + d[1] + ans + d[2] + ans + d[3]);
        ans += e[coins - ans.size()];
    }
    if ((int)ans.size() == n-1) {
        coins = press(ans + "A" + ans + "B");
        if (coins - ans.size()) {
            coins = press(ans + "A");
            if (coins - ans.size()) ans += "A";
            else ans += "B";
        } else {
            coins = press(ans + "X");
            if (coins - ans.size()) ans += "X";
            else ans += "Y";
        }
    }
    return ans;
}

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