(UVA) Deciding Victory in Go - Solution

I used Depth-First Search to solve this problem.


import java.io.*;
import java.util.*;

class Main  {
    public static char[][] matrix;
    public static boolean[][] visited;
    public static int[] vi = {-1,1,0,0};
    public static int[] vj = {0,0,-1,1};
    public static final int LENGTH = 9;
    public static int numX;
    public static int numO;
    public static int countPoint;
   
    public static void dfs(int currI, int currJ) {
        if (currI < 0 || currJ < 0 || currI >= LENGTH || currJ >= LENGTH || visited[currI][currJ] == true || matrix[currI][currJ] != '.') {
            if (currI >= 0 && currJ >= 0 && currI < LENGTH && currJ < LENGTH) {
                if (matrix[currI][currJ] == 'X') {
                    numX++;
                }
                else if (matrix[currI][currJ] == 'O') {
                    numO++;
                }
            }
            return;
        }
       
        visited[currI][currJ] = true;
        countPoint++;
        for (int i = 0; i < 4; i++) {
            int nextI = currI+vi[i];
            int nextJ = currJ+vj[i];
            dfs(nextI, nextJ);
        }
    }
   
    public static void process() throws NumberFormatException, IOException {  
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       
        String line = br.readLine();
        int numCases = Integer.parseInt(line);
        for (int i = 0; i < numCases; i++) {
            matrix = new char[LENGTH][LENGTH];
            visited = new boolean[LENGTH][LENGTH];
           
            int pointsX = 0;
            int pointsO = 0;
            for (int j = 0; j < LENGTH; j++) {
                line = br.readLine();
                for (int k = 0; k < LENGTH; k++) {
                    matrix[j][k] = line.charAt(k);
                    if (matrix[j][k] == 'X') {
                        pointsX++;
                    }
                    else if (matrix[j][k] == 'O') {
                        pointsO++;
                    }
                }
            }
       
            for (int j = 0; j < LENGTH; j++) {
                for (int k = 0; k < LENGTH; k++) {
                    numX = 0;
                    numO = 0;
                    countPoint = 0;
                    dfs(j, k);
                    if (numX > 0 && numO == 0) { // if '.'s are surrounded only by 'X'
                        pointsX += countPoint;
                    }
                    else if (numO > 0 && numX == 0) { // if '.'s are surrounded only by 'O'
                        pointsO += countPoint;
                    }
                }
            }
           
            System.out.println("Black " + pointsX + " White " + pointsO);
        }
                                                
        return;
    }
  
    public static void main(String[] args) throws NumberFormatException, IOException {
        Main m = new Main();
        m.process();

        System.exit(0);
    }
}