DouKaku?

#include <iostream>
using namespace std;

int main(){
  int road[5][4] = { {0, 1, 1, 1},
                      {2, 3, 3, 3},
                      {2, 1, 3, 3},
                      {2, 3, 3, 3},
                      {2, 3, 3, 3}
                    };

  int pattern[5][4];

  int i, j;
  for(i=0; i<5; i++){
    for(j=0; j<4; j++){
      switch(road[i][j]){
      case 0: pattern[i][j] = 1; break;
      case 1: pattern[i][j] = pattern[i][j-1]; break;
      case 2: pattern[i][j] = pattern[i-1][j]; break;
      case 3: pattern[i][j] = pattern[i][j-1] + pattern[i-1][j]; break;
      }
    }
  }
  cout << "road pattern is " << pattern[4][3] << ".\n";

  return 0;
}