I'm working on practiceit trying to prepare for a test. I'm doing tree traversals now, an I thought I had a handle on them, but I've gotten to this question and I can't get the in order or post order traversals correct.
The question is:
Suppose that the following elements are added in the specified order to an empty binary search tree:
Meg, Stewie, Peter, Joe, Lois, Brian, Quagmire, Cleveland
Write the elements of the tree above in the order they would be seen by a pre-order, in-order, and post-order traversal. Type your solutions with the elements separated by spaces and/or commas, such as:
Its vague about how they're supposed to be added, but I assume in alphabetical order, because that's how I did the starwars one before it and that worked.
So, at least as I understand it, the tree looks like:
Meg
/ \
Joe Stewie
/ \ / \
Brian Lois Peter Quagmire
\
Cleveland
The pre-order traversal, which it says I got right is: Meg, Joe, Brian, Cleveland, Lois, Stewie, Peter, Quagmire
However, its saying my in-order and post-order traversals are wrong and I cannot figure out why. I think the tree is right since the pre-order worked. Here's what I've got on the other two:
in-order: Brian, Cleveland, Joe, Lois, Meg, Peter, Stewie, Quagmire
post-order: Cleveland, Brian, Lois, Joe, Peter, Quagmire, Stewie, Meg
Any help would be greatly appreciated. Every time I think I've got a handle on traversals, something throws me for a loop.
EDIT: My tree is wrong. Q comes before S in the alphabet. It should be:
Meg
/ \
Joe Stewie
/ \ /
Brian Lois Peter
\ \
Cleveland Quagmire
The correct traversals are:
pre-order : Meg, Joe, Brian, Cleveland, Lois, Stewie, Peter, Quagmire
in-order : Brian, Cleveland, Joe, Lois, Meg, Peter, Quagmire, Stewie
post-order: Cleveland, Brian, Lois, Joe, Quagmire, Peter, Stewie, Meg
