Checking symmetry in a grid with java

Question

I need help with a game I'm doing:

The game is the following, There are two players, 'B' and 'N'. There is a grid of characters. Both players take turn to place a char (B or N depending on who they are) on the grid. Every time they place a char, I have to check whether there a symmetry is occuring. For example. There are differents types of symmetries. Horizontal and Vertical in every 2*2, 3*3 and 4*4 squares that contains the char that was just placed here. In the case of the 3*3 symmetry, the middle row or column does not take place in the symmetry.

I have done everything until now except the symmetries. I'm having some difficutly at doing them. I have an idea on how to do them but individually. Does any of you know how I could do the symmetries in one method only?

The question is a little broad. What do you have so far that attempts to solve the problem? — Paul Richter, Oct 17 '14 at 17:07
I have, for every possible symmetry, a method to solve them. For example, for the 2x2 symmetry, I ask: if the char placed is the same as the one above it, do the following: if the char on the right to it is the same as the one above it: valid symmetry if the char on the left to it is the same as the one above it: valid symmetry if the char placed is the same as the one below it, do the following: if the char on the right to it is the same as the one above it, valid symmetry if the char on the left to it is the same as the one above it, valid symmetry — Narkast, Oct 17 '14 at 17:19

score 0 · Accepted Answer · answered Oct 17 '14 at 18:49

The java code for something similar to what you described for an n by n sized grid would go something like:

boolean isHorizontallySymmetrical(char[][] grid, int n){
    int across = n / 2;

    for(int i = 0; i < n; i++){
        int right = 0
        for(int left = 0; left < across; left++){
            right = n - left - 1;

            if(grid[i][left] != grid[i][right]){
                return false;
            }
        }
    }

    return true;
}

A similar sort of thing would be needed for a vertical symmetry function.

Checking symmetry in a grid with java

1 Answers1