Submission #683102

#	Time	Username	Problem	Language	Result	Execution time	Memory
683102		bebra	Combo (IOI18_combo)	C++17	30 / 100	69 ms	556 KiB

combo

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

#define dbg(x) cerr << #x << ": " << x << endl;


const char chars[] = {'A', 'B', 'X', 'Y'};

int press(string p);

string guess_sequence(int n) {
    char first_char;
    if (press("AB")) {
        if (press("A")) {
            first_char = 'A';
        } else {
            first_char = 'B';
        }
    } else {
        if (press("X")) {
            first_char = 'X';
        } else {
            first_char = 'Y';
        }
    }
    string good;
    for (auto c : chars) {
        if (c != first_char) good += c;
    }

    mt19937 rnd(1337);

    string res = string(1, first_char);
    for (int i = 1; i < n; ++i) {
        string curr = res;
        curr.resize(n, first_char);
        curr += curr;
        curr += curr;

        curr[i] = good[0];
        curr[i + n] = good[1];
        curr[i + 2 * n] = good[2];
        if (press(curr.substr(0, 2 * n)) == i + 1) {
            if (press(curr.substr(0, n)) == i + 1) {
                res += good[0];
            } else {
                res += good[1];
            }
        } else {
            res += good[2];
        }
    }
    return res;
}

• Subtask 1: 5 / 5
• Subtask 2: 25 / 95