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Unit 3 Programming and System Development

Quick questions on Advanced data structures and algorithms: linked lists, tree traversals and recursion - WJEC A-Level Computer Science

4short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What are binary tree traversals?
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The choice of traversal matters: in-order gives sorted output, pre-order is used to copy a tree or produce prefix expressions, and post-order is used to delete a tree safely or evaluate postfix expressions.
What are recursion on structures?
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Recursion is the natural way to process trees and linked lists: the structure is defined in terms of smaller versions of itself (a tree is a node with two subtrees), so the algorithm mirrors that definition with a base case (an empty subtree or null pointer) and a recursive case.
What is q1?
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State which tree traversal outputs the values of a binary search tree in ascending order. [1 mark]
What is q2?
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State one advantage of a linked list over an array. [1 mark]

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