int
flood_fill_board (unsigned short pos, unsigned char color)
{
if (!on_board (pos) || get_point_board (pos) == color)
{
return 0;
}
empty_stack (&parse_stack);
int ret_val = 0;
unsigned char orig_color = get_point_board (pos);
set_point_board (pos, color);
++ret_val;
push_pos_stack (&parse_stack, pos);
while (pop_pos_stack (&parse_stack, &pos))
{
ret_val += flood_fill_helper (NORTH (pos), orig_color, color);
ret_val += flood_fill_helper (SOUTH (pos), orig_color, color);
ret_val += flood_fill_helper (EAST (pos), orig_color, color);
ret_val += flood_fill_helper (WEST (pos), orig_color, color);
}
return ret_val;
}
// This function receives the image and conduct floodfill operation in place.
void flood_fill(std::vector<std::string> & image,
int row,
int col,
char filler) {
if (!isValid(image, row, col) || image[row][col] == filler) {
std::cerr << "Invlid input " << row << " and " << col << std::endl;
exit(1);
}
// construct a visited matrix filled with false
std::vector<std::vector<bool> > visited;
for (unsigned int i = 0; i < image.size(); i++) {
std::vector<bool> tmp(image[i].size(), false);
visited.push_back(tmp);
}
flood_fill_helper(image, row, col, filler, visited, image[row][col]);
}
// This helper function receives the image
// and fill the specified commponent using
// dfs recurrsively.
void flood_fill_helper(std::vector<std::string> & image,
int row,
int col,
char filler,
std::vector<std::vector<bool> > visited,
char color) {
image[row][col] = filler;
visited[row][col] = true;
int dx[4] = {0, -1, 1, 0};
int dy[4] = {1, 0, 0, -1};
// we iteratively check all entries around the element
// and dfs recursively to fill it
for (unsigned int i = 0; i < 4; i++) {
int nrow = row + dx[i];
int ncol = col + dy[i];
if (isValid(image, nrow, ncol) &&
image[nrow][ncol] == color &&
!visited[nrow][ncol]) {
flood_fill_helper(image, nrow, ncol, filler, visited, color);
}
}
}