Submission #529741

#	Time	Username	Problem	Language	Result	Execution time	Memory
529741		c28dnv9q3	Nautilus (BOI19_nautilus)	C++17	100 / 100	43 ms	400 KiB

nautilus

#include <cstdio>
#include <iostream>

#define DEBUG if(false)

const int N_MAX = 512;
const int M_MAX = 5005;

int R, C, M;

uint64_t map[4096];
uint64_t cur[2][4096];

void printcur(int k) {
  for (int i = 0; i <= R + 1; i++) {
    for (int j = 0; j <= C + 1; j++) {
      putchar((cur[k][i*8 + j/64] & (1ULL << (j%64))) ? '#' : '.');
    }
    putchar('\n');
  }
  putchar('\n');
}

int main() {
  std::cin >> R >> C >> M;
  
  for (int i = 0; i < R; i++) {
    std::string s;
    std::cin >> s;
    for (int j = 0; j < C; j++) {
      if (s[j] == '.') {
        map[(i+1)*8 + (j+1)/64] |= 1ULL << ((j+1) % 64);
      }
    }
  }
  /*for (int i = 0; i < R + 2; i++) {
    map[i][0] = false;
    map[i][C+1] = false;
  }
  for (int j = 0; j < C + 2; j++) {
    map[0][j] = false;
    map[R+1][j] = false;
  }*/

  int k = 0;
  for (int i = 0; i < 4096; i++) {
    cur[k][i] = map[i];
  }

  DEBUG printf("Map at beginning\n");
  DEBUG printcur(k);

  std::string instr;
  std::cin >> instr;

  for (int i = 0; i < instr.size(); i++) {
    char c = instr[i];
    k = 1-k;
    DEBUG printf("INSTRUCTION %c (k=%d)\n", c, k);
    switch (c) {
      case 'N':
        for (int i = 8; i < 4096-8; i++) {
          cur[k][i] = cur[1-k][i+8] & map[i];
        }
        break;
      case 'E':
        for (int i = 8; i < 4096-8; i++) {
          uint64_t main = cur[1-k][i] << 1ULL;
          main &= ~1ULL;
          main |= (cur[1-k][i-1] >> 63ULL) & 1ULL;
          cur[k][i] = main & map[i];
        }
        break;
      case 'S': 
        for (int i = 8; i < 4096-8; i++) {
          cur[k][i] = cur[1-k][i-8] & map[i];
        }
        break;
      case 'W': 
        for (int i = 8; i < 4096-8; i++) {
          uint64_t main = cur[1-k][i] >> 1ULL;
          main &= ~(1ULL << 63ULL);
          main |= (cur[1-k][i+1]  & 1ULL) << 63ULL;
          cur[k][i] = main & map[i];
        }
        break;
      case '?':
        for (int i = 8; i < 4096-8; i++) {
          uint64_t m = 0;
          m |= cur[1-k][i+8];
          m |= cur[1-k][i-8];
          {
            uint64_t main = cur[1-k][i] << 1ULL;
            main &= ~1ULL;
            main |= (cur[1-k][i-1] >> 63ULL) & 1ULL;
            m |= main;
          }
          {
            uint64_t main = cur[1-k][i] >> 1ULL;
            main &= ~(1ULL << 63ULL);
            main |= (cur[1-k][i+1]  & 1ULL) << 63ULL;
            m |= main;
          }
          cur[k][i] = m & map[i];
        }
        break;
    }
    DEBUG printcur(k);
  }

  int num = 0;
  for (int i = 0; i < 4096; i++) {
    for (int j = 0; j < 64; j++) {
      num += (cur[k][i] & (1ULL << j)) ? 1 : 0;
    }
  }

  std::cout << num << std::endl;
}

Compilation message (stderr)

nautilus.cpp: In function 'int main()':
nautilus.cpp:56:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |   for (int i = 0; i < instr.size(); i++) {
      |                   ~~^~~~~~~~~~~~~~

• Subtask 1: 29 / 29
• Subtask 2: 37 / 37
• Subtask 3: 34 / 34