Implementation (in python language) of search algorithm A* (A Star).
Implementation based in the explanation of video: https://www.youtube.com/watch?v=b9fH-j_yNHU
A* or "A star" is the combination of Uniform-cost and Greedy. Uniform-cost orders by path cost or backward cost - g(n). Greedy orders by goal proximity or forward cost - h(n). A* Search orders by the sum: f(n) = g(n) + h(n)
For the graph below, the total cost is 4 and the path is S -> A -> G
For the graph below, the total cost is 6 and the path is S -> A -> D -> G
Contains a unique file called "a_star.py" that contains three classes: PriorityQueue, Node and Graph.
Output for the graphs shown previously:
Post about A* (in portuguese): http://www.geeksbr.com/2015/03/python-algoritmo-de-busca-a.html
Tested with Python 2.7 and 3.4.