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Showing posts from October, 2019

Data Structures: Traversing a Graph

Let's say we want to find the path between an origin and a destination in a graph.  We'll want to return a LinkedList that lists vertices in order from the origin to the destination.  To do this we’ll find the shortest path. In order to implement a getShortestPath method, we can take the following steps: Create a queue.  This will tell you the next vertices to visit. Create a map.  This will allow you to identify visited vertices, as well as trace your path backward. Add the origin vertex to your queue. Add the origin vertex to your map (try origin as the key, and null as the value). Then, while your queue is not empty (i.e. while you still have nodes not traversed): Retrieve & remove the next value from your queue.  We’ll call it “currentVertex” for now. If currentVertex is your destination, you’ve finished.  Calculate the path from origin to destination (using your map) and return it. If currentVertex is not your destination, retrieve th...

Sample Data Structures Exam Questions: Trees, Heaps, and Graphs

If you want to access each node in a binary tree in sorted order, how would you go about doing this?  Describe the procedure. Draw the resulting binary tree if the following values are added (as ordered below).  Is this tree complete? 56, 43, 60, 67, 80, 31, 12, 54, 65, 25, 28, 57, 50, 59 What nodes could you add to make this tree complete? How many nodes are in a full tree if the tree’s height is 11?  How many nodes are leaf nodes? What is the computational complexity of retrieving a value from a full tree? Describe the worst case for retrieval from a binary tree that is NOT full. Identify each the steps involved in removing the value “88” from the tree below. Write the code for the method public void add(Comparable value) in a Tree object.  State any assumptions made. Assume you are building a map with a tree as its backing structure.  Implement the get(Comparable key) method below.  State any assumptions made (beyond the get and set methods a...