Ruby depth-first-search function for blog post

dfs.rb

def dfs(start, target)
  paths = []
  dfs_helper(start, target, [], paths)
  paths
end

# note, no cyclic graphs allowed in dependencies, so no visited set needed
def dfs_helper(start, target, path, paths)
  path << start
  @graph[start].each do |node|
    if node == target
      path << target
      paths << path.clone
    else
      dfs_helper(node, target, path.clone, paths)
    end
  end
end