ferencd@0: #---
ferencd@0: # Excerpted from "Mazes for Programmers",
ferencd@0: # published by The Pragmatic Bookshelf.
ferencd@0: # Copyrights apply to this code. It may not be used to create training material, 
ferencd@0: # courses, books, articles, and the like. Contact us if you are in doubt.
ferencd@0: # We make no guarantees that this code is fit for any purpose. 
ferencd@0: # Visit http://www.pragmaticprogrammer.com/titles/jbmaze for more book information.
ferencd@0: #---
ferencd@0: class Wilsons
ferencd@0: 
ferencd@0:   def on(grid)
ferencd@0:     unvisited = [] 
ferencd@0:     grid.each_cell { |cell| unvisited << cell }
ferencd@0: 
ferencd@0:     first = unvisited.sample 
ferencd@0:     unvisited.delete(first) 
ferencd@0: 
ferencd@0:     while unvisited.any? 
ferencd@0:       cell = unvisited.sample 
ferencd@0:       path = [cell]
ferencd@0: 
ferencd@0:       while unvisited.include?(cell) 
ferencd@0:         cell = cell.neighbors.sample 
ferencd@0:         position = path.index(cell) 
ferencd@0:         if position
ferencd@0:           path = path[0..position] 
ferencd@0:         else
ferencd@0:           path << cell 
ferencd@0:         end
ferencd@0:       end 
ferencd@0: 
ferencd@0:       0.upto(path.length-2) do |index| 
ferencd@0:         path[index].link(path[index + 1]) 
ferencd@0:         unvisited.delete(path[index]) 
ferencd@0:       end 
ferencd@0:     end
ferencd@0: 
ferencd@0:     grid
ferencd@0:   end
ferencd@0: 
ferencd@0: end