Submission #772977

#	Time	Username	Problem	Language	Result	Execution time	Memory
772977		Alan	Combo (IOI18_combo)	C++17	100 / 100	27 ms	588 KiB

combo

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

string guess_sequence(int N) {
	string s = "AB", t, d;
	int res = press(s);
	if (res) {
		s = "A";
		res = press(s);
		t = res ? "A" : "B";
	} else {
		s = "X";
		res = press(s);
		t = res ? "X" : "Y";
	}
	if (N == 1) return t;
	for (auto& x : {'A', 'B', 'X', 'Y'}) if (x != t[0]) d.push_back(x);
	for (int i = 1; i < N-1; i++) {
		s = t;
		s.push_back(d[0]);
		s += t;
		s.push_back(d[1]);
		s.push_back(d[0]);
		s += t;
		s.push_back(d[1]);
		s.push_back(d[1]);
		s += t;
		s.push_back(d[1]);
		s.push_back(d[2]);
		res = press(s);
		if (res <= i) t.push_back(d[2]);
		else if (res == i+1) t.push_back(d[0]);
		else t.push_back(d[1]);
	}
	for (int i = 0; i < 2; i++) {
		s = t;
		s.push_back(d[i]);
		res = press(s);
		if (res == N) {
			t.push_back(d[i]);
			break;
		}
	}
	if ((int) t.size() < N) t.push_back(d[2]);
	return t;
}

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