CS Notes 15

# CS Notes 15 - o USE A STACK/RECURSION o Basic operations?...

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Data structure to map vertex names to numbers 1. Arrays o Vertex num->name O(1) o Vertex name-> num Worst case O(n) Sequential search 1. Hash table o Hash on vertex name o (Key,value)=(String,int) o Vertex num->name Can't do. Not efficient to dump and search o Vertex name->num Expected O(n) Must use both array and Hash table o Array to access names from nums o Hash table to access ums from names Graph Traversal (mapping/tracing topology) 1. Depth-first search (DFS) o Start at any arbitrary vertex and go down until you can not go any further, then go back and continue down another path o When a vertex is visited, it is marked as such in a Boolean array

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Unformatted text preview: o USE A STACK/RECURSION o Basic operations? • Visiting O(1) Do this n times • Checking if a neighbor is visited O(1) Directed: do this e times Undirected: do this 2e times • Run time: O(n+e) 1. Breadth-first search (BFS) o Enqueue root o Visit the children of the root, add children to queue o Dequeue-> this is new root o Repeat until queue is empty && all nodes visited o Basic operations • Visiting n • Check neighbor Directed: e Undirected: 2e • Enqueue n • Dequeue n o Runtime: O(n+e)...
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## This note was uploaded on 02/29/2012 for the course 198 112 taught by Professor Venugopal during the Spring '09 term at Rutgers.

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CS Notes 15 - o USE A STACK/RECURSION o Basic operations?...

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