public char[][] updateBoard(char[][] board,int[] click){

int m = board.length,n = board[0].length;

int row = click[0],col = click[1];

if (board[row][col] == 'M'){// Mine

board[row][col] = 'X';

}else {// Empty

// Get number of mines first.

int count = 0;

for (int i = -1; i < 2; i++) {

for (int j = -1; j < 2; j++) {

if (i == 0 && j == 0) continue;

int r = row + i,c= col + j;

if(r<0 || r>=m || c<0 || c<0 || c>=n) continue;

if (board[r][c] == 'M' || board[r][c] == 'X') count++;

}

}

if (count > 0){// If it is not a 'B',stop further DFS

board[row][col] = (char) (count + '0');

}else {// Continue DFS to adjacent cells

board[row][col] = 'B';

for (int i = -1;i<2;i++){

for (int j = -1; j <2 ; j++) {

if (i==0 && j==0) continue;

int r = row + i,c = col + j;

if (r<0 || r>=m || c<0 || c>=n) continue;

if (board[r][c] == 'E') updateBoard(board,new int[]{r,c});

}

}

}

}

return board;

}

public static void main(String[] args) {

char[][] board = {{'E', 'E', 'E', 'E', 'E'},

{'E', 'E', 'M', 'E', 'E'},

{'E', 'E', 'E', 'E', 'E'},

{'E', 'E', 'E', 'E', 'E'}};

int[] click = {3,0};

UpdateBoard updateBoard = new UpdateBoard();

char[][] r = updateBoard.updateBoard(board,click);

System.out.println(Arrays.asList(Arrays.asList(r)));

}