Submission #853526

#	Time	Username	Problem	Language	Result	Execution time	Memory
853526		lamter	Combo (IOI18_combo)	C++17	100 / 100	12 ms	1748 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>

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

	std::string ans = press("AB") ? press("A") ? "A" : "B" : press("X") ? "X" : "Y";

	KEYS.erase(std::find(KEYS.begin(), KEYS.end(), ans[0]));

	while ((int) ans.size() <= n - 2) {
		int t = press(ans + KEYS[0] + KEYS[0] + ans + KEYS[0] + KEYS[1] + ans + KEYS[1] + KEYS[0]);

		if (t == (int) ans.size())
			ans = ans + KEYS[2];
		if (t == (int) ans.size() + 1) {
			int tt = press(ans + KEYS[1] + KEYS[2]);
			if (tt == (int) ans.size())
				ans = ans + KEYS[0] + KEYS[2];
			if (tt == (int) ans.size() + 1)
				ans = ans + KEYS[1] + KEYS[1];
			if (tt == (int) ans.size() + 2)
				ans = ans + KEYS[1] + KEYS[2];
		}
		if (t == (int) ans.size() + 2) {
			int tt = press(ans + KEYS[0] + KEYS[0]);
			if (tt == (int) ans.size())
				ans = ans + KEYS[1] + KEYS[0];
			if (tt == (int) ans.size() + 1)
				ans = ans + KEYS[0] + KEYS[1];
			if (tt == (int) ans.size() + 2)
				ans = ans + KEYS[0] + KEYS[0];
		}
	}

	while ((int) ans.size() != n) {
		if (press(ans + KEYS[0]) != (int) ans.size()) {
			ans = ans + KEYS[0];
			break;
		}
		if (press(ans + KEYS[1]) != (int) ans.size()) {
			ans = ans + KEYS[1];
			break;
		}
		ans = ans + KEYS[2];
	}

	return ans;
}

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