public class checkqi{
     int i=0,j=0;
     int x,y;
     static int dingwei[][]=new int[18][18];
     public checkqi()
     {

     }

     public qizi check(int x_, int y_,int sider) {
         qizi qi = new qizi();
         x = x_;
         y = y_;
         if (x < 29 || y < 12 || x > 530 || y > 513) {
             return null;
         } else {
             if ((x_ - 30) % 29 > 14.5) {
                 j = (int) ((x_ - 30) / 29) + 1;
             } else {
                 j = (int) (x_ - 30) / 29;
             }
             if ((y_ - 15) % 29 > 14.5) {
                 i = (int) ((y_ - 15) / 29) + 1;
             } else {
                 i = (int) (y_ - 15) / 29;
             }
             x = j * 29 + 30;
             y = i * 29 + 15;
             if (dingwei[i][j] == 0) {
                 if (sider == 1) {
                     dingwei[i][j] = 1;
                 }
                 if (sider == 2) {
                     dingwei[i][j] = 2;
                 }
                 qi.x = x;
                 qi.y = y;
                 qi.sider = sider;
                 return qi;
             }
             return null; //當那個點已經有棋時,點擊無效
         }
     }
}