Traversals

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Traversals

• Common set of algoritms on trees are traversals
• A way of visiting all the nodes of a tree
• Visit is defined as performing one operation on
  a node

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Traversals

• Three basic traversals
• Preorder
• Postorder
• Inorder

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Preorder Traversal
Algorithm preOrder(v) visit(v) for each child w
of v preorder (w)

• A traversal visits the nodes of a tree in a
  systematic manner
• In a preorder traversal, a node is visited before
  its descendants
• Application print a structured document

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Make Money Fast!
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1. Motivations
References
2. Methods
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2.3 BankRobbery
2.1 StockFraud
2.2 PonziScheme
1.1 Greed
1.2 Avidity
Demo
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Postorder Traversal
Algorithm postOrder(v) for each child w of
v postOrder (w) visit(v)

• In a postorder traversal, a node is visited after
  its descendants
• Application compute space used by files in a
  directory and its subdirectories

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cs16/
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todo.txt1K
homeworks/
programs/
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DDR.java10K
Stocks.java25K
h1c.doc3K
h1nc.doc2K
Robot.java20K
Demo
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Inorder Traversal

• In an inorder traversal a node is visited after
  its left subtree and before its right subtree
• More later when we discuss binary trees

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Traversal Worksheet
Postorder
Preorder
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Linked Structure for Trees

• A node is represented by an object storing
• Element
• Parent node
• Sequence of children nodes
• Node objects implement the Position ADT

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