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# When do i say that a binary search tree is unique?!

Greenhorn
Posts: 27
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Hi,
given the following:

90,50,20,5,25,75,66,80,150,95,92,111,175,166,200.

i constructed the binary tree and the traversal was preorder traversal : root, left, right

and then Is the tree unique?!

yes , the tree is unique,

i dont understand why?!

Ranch Hand
Posts: 266
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given the following:

90,50,20,5,25,75,66,80,150,95,92,111,175,166,200.

i constructed the binary tree and the traversal was preorder traversal : root, left, right

and then Is the tree unique?!

yes , the tree is unique,

i dont understand why?!

Because it's a binary search tree. With a regular binary tree, the order of the elements doesn't matter, so the pre-order traversal of [3,2,4] could be:

But with a binary search tree, you start with 3, and the insert 2 to the left (because it's less than 3) and insert 4 into the right (because it's more than 3), resulting in:

Marshal
Posts: 79233
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Please explain what you mean by the tree being unique.

Greenhorn
Posts: 27
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Hi campbell ritchie, i actually asked the question to a friend of mine!

she told me that the tree is unique meaning that with the preorder and inorder traversal the tree has JUST ONE SHAPE!!

not many!