can a node be inserted at a non leaf position in a binary search tree?

can a node be inserted in a non leaf position in a binary search tree ?

for eg. if we have the following set of numbers to be arranged as a binary serach tree :-

20.,17,15,19,23,25....

so there is more than 1 way these numbers can be arranged as a bst :-

1.        20
      17      23
   15    19      25
   

2.     20开发者_C百科
   15      23
     17       25
       19
   

3. 25 make it a root and place the other nodes accordingly....

I think you could devise some way to do that. But the normal algorithm for inserting into a BST doesn't do it and I don't see any reason why would you want to do that. Also, I don't know about any other publicly known algorithm that does that.

A binary search tree is just a tree with certain properties. You can use different algorithms for inserting nodes into such a tree, as long as these algorithms ensure that the properties required for a BST hold. So, yes, you can add nodes in other places than leafes if you want to.