Submission #1230187

#	Time	Username	Problem	Language	Result	Execution time	Memory
1230187		fauntleroy	Combo (IOI18_combo)	C++20	100 / 100	7 ms	484 KiB

combo

#include <iostream>
#include <cstdio>
#include <vector>
#include <array>
#include <string>
#include <algorithm>
#include <numeric>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <cmath>
#include <climits>
#include <iomanip>
#include <limits>
#include <tuple>
#include <stack>
#include <bitset>
#include <cstring>
#include <sstream>
#include <functional>
#include <random>
#include "combo.h"
using namespace std;

string guess_sequence(int N) {
	string ans;
	if (press("AB")) {
		if (press("A") == 1)
			ans.push_back('A');
		else
			ans.push_back('B');
	}
	else if (press("X") == 1)
		ans.push_back('X');
	else
		ans.push_back('Y');

	if (N == 1)
		return ans;

	char p[3];
	int k = 0;
	for (char c : {'A', 'B', 'X', 'Y'})
		if (c != ans[0])
			p[k++] = c;

	for (int i = 1; i < N - 1; i++) {
		string ask;
		ask += ans; ask += p[0];
		ask += ans; ask += p[1]; ask += p[0];
		ask += ans; ask += p[1]; ask += p[1];
		ask += ans; ask += p[1]; ask += p[2];
		int q = press(ask);
		if (q == ans.size() + 2)
			ans.push_back(p[1]);
		else if (q == ans.size() + 1)
			ans.push_back(p[0]);
		else
			ans.push_back(p[2]);
	}
	for (int i = 0; i < 2; ++i)
		if (press(ans + p[i]) == N)
			return ans + p[i];

	return ans + p[2];
}

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