Rotations in splay trees
Just follow the algorithm. First you have to do a zag-zag-rotation, which gives you

0
 \
  1
   \
    4
   / 
  3    
 /      
2        


Then you have to do another zag-zag-rotation and you obtain as the result of splay(4) the tree

    4
   / 
  1   
 / \ 
0   3      
   /  
  2