Method dfs

java/1020-number-of-enclaves.java:22–31

(int r, int c, int[][] board)

        return c;
    }
    public void dfs(int r, int c, int[][] board){
        if(r<0 || c<0 || r>board.length-1 || c>board[0].length-1 || board[r][c] != 1) return;

        board[r][c] = 2;

        dfs(r+1, c, board);
        dfs(r-1, c, board);
        dfs(r, c+1, board);
        dfs(r, c-1, board);
    }
    public int numEnclaves(int[][] board) {
        int n=board.length, m=board[0].length;