Submission #305478

#	Time	Username	Problem	Language	Result	Execution time	Memory
305478		talant117408	Combo (IOI18_combo)	C++17	30 / 100	61 ms	568 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>

using namespace std;/*

string guess_sequence(int n);

namespace {

constexpr int MAX_N = 2000;
constexpr int MAX_NUM_MOVES = 8000;

int N;
std::string S;

int num_moves;

void wrong_answer(const char *MSG) {
  printf("Wrong Answer: %s\n", MSG);
  exit(0);
}

}  // namespace

int press(std::string p) {
  if (++num_moves > MAX_NUM_MOVES) {
    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;
}

int main() {
  char buffer[MAX_N + 1];
  if (scanf("%s", buffer) != 1) {
    fprintf(stderr, "Error while reading input\n");
    exit(1);
  }
  S = buffer;
  N = S.length();

  num_moves = 0;
  std::string answer = guess_sequence(N);
  if (answer != S) {
    wrong_answer("wrong guess");
    exit(0);
  }
  printf("Accepted: %d\n", num_moves);
  return 0;
}
*/
string guess_sequence(int n) {
	string s = "";
	
	vector <char> moves;
	char forbid;
	int coins;
	
	coins = press("AB");
	if(coins){
		coins = press("A");
		if(coins) forbid = 'A', s += 'A';
		else forbid = 'B', s += 'B';
	}
	else{
		coins = press("X");
		if(coins) forbid = 'X', s += 'X';
		else forbid = 'Y', s += 'Y';
	}
	
	for(auto to : {'A', 'B', 'X', 'Y'}){
		if(to == forbid) continue;
		moves.push_back(to);
	}
	
	for(int i = 1; i < n; i++){
		coins = press(s+moves[0]+s+moves[1]);
		if(coins == i+1){
			coins = press(s+moves[0]);
			if(coins == i+1){
				s += moves[0];
			}
			else{
				s += moves[1];
			}
		}
		else{
			s += moves[2];
		}
	}
	
	return s;
}

• Subtask 1: 5 / 5
• Subtask 2: 25 / 95