Tag Archives: algorithms

Dijkstra Shortest Path using Python

Posted on August 24, 2010 by nolfonzo

This post uses python and Dijkstra’s algorithm to calculate the shortest path given a start node (or vertex), an end node and a graph. The function will return the distance from the start node to the end node, as well … Continue reading →

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Cyclic Linked List – finding the start of the loop using Python

Posted on July 18, 2010 by nolfonzo

I’d blogged previously about writing a python function to find out whether a linked list is cyclic or acyclic – it’s worth a read before tackling this one. The challenge here is to return the node that is at the … Continue reading →

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Binary Search Tree – Lowest Common Ancestor – Python

Posted on June 1, 2008 by nolfonzo

The last problem in the Trees chapter of Programming Interviews Exposed was about finding the lowest common ancestor between two nodes of a binary search tree. Starting from the head, if you find that the nodes that you’re looking for … Continue reading →

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Tree Traversal – Python

Posted on May 31, 2008 by nolfonzo

Another question posed in the Programming Interviews Exposed book. A pre-ordered traversal of a binary tree (counterclockwise starting at root, printing nodes as you encounter them) is pretty straight forward, and a very natural thing to implement with recursion: A … Continue reading →

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Linked List – Cyclic or Acyclic?

Posted on May 30, 2008 by nolfonzo

Another problem in the Programming Interviews Exposed book (see previous post) is to determine whether a Linked List is cyclic or not. The most obvious way to do this is to iterate over the list, checking whether the next element … Continue reading →

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More on Linked Lists – flattening and unflattening

Posted on May 30, 2008 by nolfonzo

More from the Programming Interviews Exposed book (see last post). In this problem you take a double linked list (where each node knows its previous and next nodes) with child elements, and flatten it. Then unflatten it back to its … Continue reading →

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Linked List Interview questions

Posted on May 29, 2008 by nolfonzo

I hadn’t done much programming for a while and thought I’d best brush up on some basic data structures and algorithm. The following is from Programming Interviews Exposed. I implemented some of the Linked List stuff in the first section … Continue reading →

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