Submission #209720

#	Time	Username	Problem	Language	Result	Execution time	Memory
209720		quocnguyen1012	Combo (IOI18_combo)	C++14	100 / 100	39 ms	744 KiB

combo

#ifdef LOCAL
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <string>

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;
}
#endif // LOCAL
#ifndef LOCAL
#include "combo.h"
#endif // LOCAL

#include<bits/stdc++.h>

using namespace std;

string guess_sequence(int N)
{
  string res;
  char first;
  string can  = "ABXY";
  if(press("AB")){
		if(press("A"))
			first = 'A';
		else first = 'B';
  }
  else{
		if(press("X"))
			first = 'X';
		else first = 'Y';
  }
  res += first;
  can.erase(can.find(first), 1);
  if(N == 1) return res;
  for(int i = 2; i < N; ++i){
		int now = press(res + can[0] + res + can[1] + can[0] + res + can[1] + can[1] + res + can[1] + can[2]);
		if(now == i - 1) res += can[2];
		else if(now == i) res += can[0];
		else res += can[1];
  }
  if(press(res + can[0]) == N) res += can[0];
  else if(press(res + can[1]) == N) res += can[1];
  else res += can[2];
  return res;
}

#ifdef LOCAL

int main() {
	if(fopen("A.INP", "r")) freopen("A.INP", "r", stdin);
  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;
}

#endif // LOCAL

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