Submission #1159608

#	Time	Username	Problem	Language	Result	Execution time	Memory
1159608		trvhung	Combo (IOI18_combo)	C++20	100 / 100	7 ms	484 KiB

combo

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

const char ch[4] = {'A', 'B', 'X', 'Y'};

// int press(string p) {
// 	cout << "ASK " << p << endl;
// 	int res; cin >> res;
// 	return res;
// } 

char getFirst(string s) {
	char bck = s.back(); s.pop_back();
	return press(s) == 1 ? s[0] : bck;
}

string guess_sequence(int N) {
	char first = press("AB") == 0 ? getFirst("XY") : getFirst("AB");
	int idFirst;
	for (int i = 0; i < 4; ++i)
		if (ch[i] == first)
			idFirst = i;

	vector<char> remain;
	for (int i = 0; i < 4; ++i)
		if (i != idFirst)
			remain.push_back(ch[i]);

	string s = ""; s += first;

	if (N == 1) return s;

	for (int i = 2; i < N; ++i) {
		string p = s + remain[0] + s + remain[1] + remain[0] + s + remain[1] + remain[1] + s + remain[1] + remain[2];
		int ask = press(p);
		if (ask == i) 
			s += remain[0];
		else if (ask == i + 1)
			s += remain[1];
		else 
			s += remain[2];
	}

	string p = s + 'A' + s + 'B';
	if (press(p) == N) {
		if (press(s + 'A') == N) 
			s += 'A';
		else
			s += 'B';
	} else {
		if (press(s + 'X') == N)
			s += 'X';
		else 
			s += 'Y';
	}

	return s;
}

// int main() {
// 	int n;
// 	cin >> n;
// 	cout << guess_sequence(n);
// 	return 0;
// }

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