Submission #1264622

#	Time	Username	Problem	Language	Result	Execution time	Memory
1264622		wedonttalkanymore	Combo (IOI18_combo)	C++20	97 / 100	7 ms	484 KiB

combo

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

//#define int long long
#define pii pair<ll, ll>
#define fi first
#define se second

const ll MAXX = 2e5 + 5, inf = 1e9, mod = 1e9 + 7, block = 320, lim = 16;

//namespace {
//
//constexpr int MAX_N = 2000;
//constexpr int MAX_NUM_MOVES = 8000;
//
//int N;
//std::string S;
//
//int num_moves = 0;
//
//void wrong_answer(const char *MSG) {
//  printf("Wrong Answer: %s\n", MSG);
//  exit(0);
//}
////
////}  // namespace
////
////int press(std::string p) {
////	cout << p << ' ' << num_moves << '\n';
////  if (++num_moves > MAX_NUM_MOVES) {
////  	cout << num_moves << '\n';
////    wrong_answer("too many moves");
////  }
////  int len = p.length();
////  if (len > 4 * N) {
////    wrong_answer("invalid press");
////  }
////  for (int i = 0; i < len; ++i) {
////    if (p[i] != 'A' && p[i] != 'B' && p[i] != 'X' && p[i] != 'Y') {
////      wrong_answer("invalid press");
////    }
////  }
////  int coins = 0;
////  for (int i = 0, j = 0; i < len; ++i) {
////    if (j < N && S[j] == p[i]) {
////      ++j;
////    } else if (S[0] == p[i]) {
////      j = 1;
////    } else {
////      j = 0;
////    }
////    coins = std::max(coins, j);
////  }
////  return coins;
////}

string convert(string &ans, vector <char> &unbanned) {
	string t = ans;
	t += unbanned[0];
	t += unbanned[0];
	t += ans;
	t += unbanned[0];
	t += unbanned[1];
	t += ans;
	t += unbanned[0];
	t += unbanned[2];
	t += ans;
	t += unbanned[1];
	return t;
}

map <char, int> mp;
string guess_sequence(int N) {
	mp['A'] = 1, mp['B'] = 2, mp['X'] = 3, mp['Y'] = 4;
	string ans = "";
	int begin = 0;
	int t = press("AB");
	if (t) {
		int t1 = press("A");
		if (t1) ans += "A";
		else ans += "B";
		if (t1) begin = 1;
		else begin = 2;
	}
	else {
		int t1 = press("X");
		if (t1) ans += "X";
		else ans += "Y";
		if (t1) begin = 3;
		else begin = 4;
	}
	if ((int)ans.size() == N) return ans;
	vector <char> unbanned;
	for (auto i : mp) {
		if (begin != i.second) unbanned.push_back(i.first);
	}
	while((int)ans.size() < N - 1) {
        string pre = convert(ans, unbanned);
        int got = press(pre);
        int base = ans.size();
        if (got == base + 2) {
            ans += unbanned[0];
        } else if (got == base + 1) {
            ans += unbanned[1];
        } else if (got == base) {
            ans += unbanned[2];
        } else {
            bool ok = false;
            for (char c : unbanned) {
                string tmp = ans;
                tmp += c;
                int r = press(tmp);
                if (r == base + 1) {
                    ans += c;
                    ok = true;
                    break;
                }
            }
            if (!ok) {
                vector<char> ALL = {'A','B','X','Y'};
                for (char c : ALL) {
                    string tmp = ans;
                    tmp += c;
                    int r = press(tmp);
                    if (r == base + 1) {
                        ans += c;
                        ok = true;
                        break;
                    }
                }
            }
            if (!ok) {
                ans += unbanned[0];
            }
        }
	}
	for (auto i : unbanned) {
		string tmp = ans;
		tmp += i;
		int tt = press(tmp);
		if (tt == N) return tmp;
	}
	vector<char> ALL = {'A','B','X','Y'};
	for (char c : ALL) {
		string tmp = ans;
		tmp += c;
		int tt = press(tmp);
		if (tt == N) return tmp;
	}
	ans += unbanned[0];
	return ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 92 / 95