Spanning tree

http://en.wikipedia.org/wiki/Spanning_tree

Quick-sort

https://class.coursera.org/algo-006/lecture/23

Algorithms: Tree traversal, Depth-first-search (DFS), Breadth-first-search (BFS)

http://en.wikipedia.org/wiki/Depth-first_search
http://en.wikipedia.org/wiki/Tree_traversal
http://en.wikipedia.org/wiki/Iterative_deepening_depth-first_search

Q: how to invert binary tree?
DO:  pascal triangle problems
DO: cases using stacks
DO:Graph algs
LRN: Quick sort, insert sort, bobble sort, selection sort, binary tree search
graph search.     

Code Katas

Code katas:
http://www.codekatas.org/
http://www.codingdojo.org/cgi-bin/index.pl?KataCatalogue
http://codekata.com/
https://laracasts.com/series/code-katas-in-php
http://en.wikipedia.org/wiki/Kata_(programming)

Also see
how to get job in facebook
Code problems:
http://www.careercup.com/page

Coding exercises problems (from facebook interview email)

A few coding samples (from facebook interview email)

• Cracking the Coding Interview
• Career cup
• Code Chef
• Project Euler
• Topcoder 
• CoderByte

ReactPHP lib - event driven development

Docker - continues integration platform