分治法-棋盘覆盖 java

public void chessboard(int tr,int tc,int dr,int dc,int size)
{
    if(size==1)
    return;
    int t=tile++,
    s=size/2;
    if(dr<tr+s&&dc<tc+s)
     chessboard(tr,tc,dr,dc,s);
    else
    {
     board[tr+s-1][tc+s-1]=t;
        chessboard(tr,tc,tr+s-1,tc+s-1,s);
    }
 
    if(dr<tr+s&&dc>=tc+s)
     chessboard(tr,tc+s,dr,dc,s);
    else
    {
     board[tr+s-1][tc+s]=t;
        chessboard(tr,tc+s,tr+s-1,tc+s,s);
    }

    if(dr>=tr+s&&dc<tc+s)
     chessboard(tr+s,tc,dr,dc,s);
    else
    {
    board[tr+s][tc+s-1]=t;
        chessboard(tr+s,tc,tr+s,tc+s-1,s);
    }