bfs

traverse.py

import Queue

class node( object ):
    def __init__( self, value, children = None ):
        self.value = value
        self.children = children or []

def traverse( root ):
    # seen = set()
    q = Queue.Queue() # stack - Breadth-First
    # q = Queue.LifoQueue() # stack - Depth-First
    # q = Queue.PriorityQueue() # stack - Dijkstra
    q.put( root )
    while( not q.empty() ):
        node = q.get()
        # if node in seen:
        #     continue
        # seen.add( node )

        print node.value
        # if ...
        for child in node.children:
            q.put( child )
    return None

n = node( 1, [ 
    node( 11, [
        node( 111 )
        ] ),
    node( 12, [
        node( 121 ),
        node( 122 )
        ] ),
    node( 13 ),
    ] )

traverse( n )