Queue and Tree in C Yang Zhengwei CSCI2100B Data Structures Tutorial 5 1

Queue ticket office of the Ocean park? 2

Queue Overview First In First Out (FIFO) Enqueue Dequeue 3

Queue Implementation A queue may be implemented using linked-list or array Implement a queue using array 4

Queue Implementation Implementing a queue using circular array 5

Queue Implementation createQueue 6

Queue Implementation enqueue 7

Queue Implementation dequeue 8

Queue Implementation isEmpty, isFull 9

Queue Implementation front, makeEmpty 10

Binary Tree Overview Binary tree – Degree of tree is 2 11

Trees – traversal (Recursion) Preorder 12

Trees – traversal (Recursion) Inorder 13

Trees – traversal (Recursion) Postorder 14

Trees - traversal Preorder A B D G H E C F I Inorder G D H B E A F I C Postorder G H D E B I F C A 15 A B C D E F I G H

Traversal(non-recursion) INORDER(node) parentStack = empty stack while (not parentStack.isEmpty() or node ≠ null) if (node ≠ null) parenStack.push(node) node = node.left else node = parentStack.pop() visit(node) node = node.right

A B E CD C B A A B E CD B A A B E CD D A A B E CD A A B E CD E A B E CD Output: C Output: Output: C B Output: C B DOutput: C B D A Output: C B D A E

Traversal(non recursion) PREORDER(node) parentStack = empty stack while (not parentStack.isEmpty() or node ≠ null) if (node ≠ null) visit(node) if (node.right ≠ null) parentStack.push(node.right) node = node.left else node = parentStack.pop() Preorder

POSTORDER (node) parentStack = empty stack lastnodevisited = null while (not parentStack.isEmpty() or node ≠ null) if (node ≠ null) parentStack.push(node) node = node.left else peeknode = parentStack.peek() if (peeknode.right ≠ null and lastnodevisited ≠ peeknode.right) /* if right child exists AND traversing node from left child, move right */ node = peeknode.right else visit(peeknode) lastnodevisited = parentStack.pop() Traversal(non recursion) Postorder