Merge pull request #43 from sanchojaf/master

Adding Towers of Hanoi using Stack

Author: sagivo

README.md

@@ -5,9 +5,9 @@ Algorithms playground for common questions solved in ruby syntax.
 In case you want to prepare yourself for a job interview - try to solve it yourself first, then have a look here. 
 
 # Why?
-I interviewed with [Google](https://github.com/sagivo/algorithms/blob/master/src/google-interview-tips.md), [Facebook](https://github.com/sagivo/algorithms/blob/master/src/facebook-interview-tips.md), [LinkedIn](https://github.com/sagivo/algorithms/blob/master/src/linkedin-interview.md), Twitter and others. I also interviewed others myself. 
-Sometimes it looks like they all ask you the same "out of the box" questions that don't really check knowledge but memorization of the same tricks. 
-This is my way of saying - change your interview style. There are lots of smart people out there, this is not the best way to find them. 
+I interviewed with [Google](https://github.com/sagivo/algorithms/blob/master/src/google-interview-tips.md), [Facebook](https://github.com/sagivo/algorithms/blob/master/src/facebook-interview-tips.md), [LinkedIn](https://github.com/sagivo/algorithms/blob/master/src/linkedin-interview.md), Twitter and others. I also interviewed others myself.
+Sometimes it looks like they all ask you the same "out of the box" questions that don't really check knowledge but memorization of the same tricks.
+This is my way of saying - change your interview style. There are lots of smart people out there, this is not the best way to find them.
 
 # Problems
 
@@ -53,7 +53,8 @@ This is my way of saying - change your interview style. There are lots of smart
 | [Eucliden and Extended Eucliden algorithm](http://en.wikipedia.org/wiki/Extended_Euclidean_algorithm) | [click](https://github.com/sagivo/algorithms/blob/master/src/gcd.rb) |
 | Suggest index of a number in an array | [click](https://github.com/sagivo/algorithms/blob/master/src/sugget_index_in_array.rb) |
 | [Range minimum query sparse table algorithm](http://en.wikipedia.org/wiki/Range_minimum_query) | [click](https://github.com/sagivo/algorithms/blob/master/src/rmq.rb) |
-| [Insertion Sort](https://en.wikipedia.org/wiki/Insertion_sort) | [click](https://github.com/sagivo/algorithms/blob/master/src/insertion_sort.rb) |
+| [Insertion Sort](https://en.wikipedia.org/wiki/Insertion_sort) | [click](https://github.com/sagivo/algorithms/blob/master/src/insertion_sort.rb) |
+| [Towers of Hanoi using Stack](https://en.wikipedia.org/wiki/Tower_of_Hanoi) | [click](blob/master/src/towers_of_hanoi_with_stack.rb)
 | [Tarjan's strongly connected components finder](https://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm) | [click](https://github.com/sagivo/algorithms/blob/master/src/tarjan.rb) |
 
 
@@ -62,5 +63,5 @@ Simply run `ruby some_file.rb` to execute the algorithm. At the bottom of each f
 example: `ruby brackets_combinations.rb` will print: 
 `["((()))", "(()())", "(())()", "()(())", "()()()"]`. 
 
-# Contribute 
+# Contribute
 Did you find a bug? any way to do it better? please feel free to pull-request it :)

src/towers_of_hanoi_with_stack.rb

@@ -0,0 +1,16 @@
+def towers(list)
+ while !list.empty?
+ n, src, dst, aux = list.pop
+ if n == 1
+ puts "Move disk from #{src} to #{dst}"
+ else
+ list.push [n-1, aux, dst, src]
+ list.push [1, src, dst, aux]
+ list.push [n-1, src, aux, dst]
+ end
+ end
+end
+
+list = []
+list.push([3, "a", "c", "b"])
+towers(list)