Submission #567600

#	Time	Username	Problem	Language	Result	Execution time	Memory
567600		valerikk	Combo (IOI18_combo)	C++17	97 / 100	43 ms	556 KiB

combo

#include "combo.h"
#include <vector>
#include <string>
#include <algorithm>
#include <assert.h>
#include <iostream>

std::string guess_sequence(int N) {
	std::vector<char> buttons = { 'A', 'B', 'X', 'Y' };

	int first = 0;
	while (first < 3 && press({ buttons[first] }) == 0) {
		++first;
	}

	char Y = buttons[first];
	char A = buttons[(first + 1) % 4];
	char B = buttons[(first + 2) % 4];
	char X = buttons[(first + 3) % 4];

	std::string S = { Y };

	while ((int) S.size() < N - 1) {
		std::string p = S + A + A + S + A + B + S + A + X + S + B;

		// std::cerr << S << " " << p << "\n";

		int coins = press(p);

		int matching = coins - (int) S.size();

		if (matching == 0) {
			S += X;
		} else if (matching == 1) {
			S += B;
		} else {
			S += A;
		}
	}

	if ((int) S.size() < N) {
		if (press(S + A) == N) {
			S += A;
		} else if (press(S + B) == N) {
			S += B;
		} else {
			S += X;
		}
	}

	std::cerr << S << "\n";

	return S;
}

• Subtask 1: 5 / 5
• Subtask 2: 92 / 95