Submission #998577

#	Time	Username	Problem	Language	Result	Execution time	Memory
998577		overwatch9	Combo (IOI18_combo)	C++17	100 / 100	21 ms	952 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
string guess_sequence(int N) {
	string ans = "AB";
   	int res = press(ans);
	// cout << "RES1: " << res << '\n';
   	if (res >= 1) {
     	ans = "A";
      	res = press(ans);
		if (res == 0)
			ans = "B";
  	} else {
		ans = "X";
		res = press(ans);
		if (res == 0)
			ans = "Y";
	}
	vector <char> c(3);
	if (ans[0] == 'A')
		c = {'B', 'X', 'Y'};
	if (ans[0] == 'B')
		c = {'A', 'X', 'Y'};
	if (ans[0] == 'X')
		c = {'A', 'B', 'Y'};
	if (ans[0] == 'Y')
		c = {'A', 'B', 'X'};

	for (int i = 1; i+1 < N; i++) {
		string s = ans;
		s.push_back(c[0]);
		for (int j = 0; j < 3; j++) {
			s.append(ans);
			s.push_back(c[1]);
			s.push_back(c[j]);
		}
		// cout << "guess: " << s << '\n';
		res = press(s);
		// cout << "result: " << res << '\n';
		if (res == i+1)
			ans.push_back(c[0]);
		else if (res == i+2)
			ans.push_back(c[1]);
		else
			ans.push_back(c[2]);
	}
	if (N >= 2) {
		ans.push_back(c[0]);
		res = press(ans);
		if (res == N) {
			return ans;
		}
		ans.pop_back();
		ans.push_back(c[1]);
		res = press(ans);
		if (res == N)
			return ans;
		ans.back() = c[2];
	}
	return ans;
}

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