Update README.md

README.md

@@ -47,6 +47,8 @@ Directory Structure
     <td><img src="https://github.com/zhm-real/path-planning-algorithms/blob/master/Search-based%20Planning/gif/Astar.gif" alt="astar" width="400"/></a></td>
     <td><img src="https://github.com/zhm-real/path-planning-algorithms/blob/master/Search-based%20Planning/gif/Bi-Astar.gif" alt="biastar" width="400"/></a></td>
   </tr>
+</table>
+<table>
   <tr>
     <td><img src="https://github.com/zhm-real/path-planning-algorithms/blob/master/Search-based%20Planning/gif/ARA_star.gif" alt="arastar" width="400"/></a></td>
     <td><img src="https://github.com/zhm-real/path-planning-algorithms/blob/master/Search-based%20Planning/gif/LRTA_star.gif" alt="lrtastar" width="400"/></a></td>