BOJ 14500, 테트로미노

Source: BOJ 14500 테트로미노

#include <bits/stdc++.h>
using namespace std;

int n, m;
int board[510][510];

const char block[19][4][5] = {
  {
    {"1111"},
    {"0000"},
    {"0000"},
    {"0000"}
  },
  {
    {"1000"},
    {"1000"},
    {"1000"},
    {"1000"}
  },
  {
    {"1000"},
    {"1000"},
    {"1100"},
    {"0000"}
  },
  {
    {"1110"},
    {"1000"},
    {"0000"},
    {"0000"}
  },
{
    {"1100"},
    {"0100"},
    {"0100"},
    {"0000"}
  },
  {
    {"0010"},
    {"1110"},
    {"0000"},
    {"0000"}
  },
  {
    {"0100"},
    {"0100"},
    {"1100"},
    {"0000"}
  },
  {
    {"1110"},
    {"0010"},
    {"0000"},
    {"0000"}
  },
  {
    {"1100"},
    {"1000"},
    {"1000"},
    {"0000"}
  },
  {
    {"1000"},
    {"1110"},
    {"0000"},
    {"0000"}
  },
  {
    {"1000"},
    {"1100"},
    {"0100"},
    {"0000"}
  },
  {
    {"0110"},
    {"1100"},
    {"0000"},
    {"0000"}
  },
  {
    {"0100"},
    {"1100"},
    {"1000"},
    {"0000"}
  },
  {
    {"1100"},
    {"0110"},
    {"0000"},
    {"0000"}
  },
  {
    {"1110"},
    {"0100"},
    {"0000"},
    {"0000"}
  },
  {
    {"1000"},
    {"1100"},
    {"1000"},
    {"0000"}
  },
  {
    {"0100"},
    {"1110"},
    {"0000"},
    {"0000"}
  },
  {
    {"0100"},
    {"1100"},
    {"0100"},
    {"0000"}
  },
  {
    {"1100"},
    {"1100"},
    {"0000"},
    {"0000"}
  }
};

int calc(int a, int b, int k){
  int ret = 0;
  for(int i=0; i<4; i++){
    for(int j=0; j<4; j++){
      ret += (block[k][i][j] - '0') * board[i+a][j+b];
    }
  }
  return ret;
}

int main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin>>n>>m;
  for(int i=0; i<n; i++){
    for(int j=0; j<m; j++){
      cin>>board[i][j];
    }
  }
  for(int i=0; i<n+3; i++){
    for(int j=m; j<m+3; j++){
      board[i][j] = -100000;
    }
  }
  for(int i=n; i<n+3; i++){
    for(int j=0; j<m+3; j++){
      board[i][j] = -100000;
    }
  }
  int mx = 0;
  for(int i=0; i<n; i++){
    for(int j=0; j<m; j++){
      for(int k=0; k<19; k++){
        mx = max(mx, calc(i, j, k));
      }
    }
  }
  cout<<mx<<'\n';
  
}