first_graph

class Node:

    # Constructor to initialize the node object
    def __init__(self, data, neighbors=[]):
        self.data = data
        self.neighbors = []

class Graph:
    def __init__(self):
        self.head = None

    def create_graph(self, adj_dict):
        graph = Graph()
        keys = sorted(adj_dict.keys())
        nodes = self.create_nodes(keys)
        for key in keys:
            the_neighbors = adj_dict[key]
            #move to method in Node
            for neighbor in the_neighbors:
                nodes[key].neighbors.append(nodes[neighbor])
        self.head = nodes['A']
        return graph

    def create_nodes(self, keys):
        node_dict = {}
        for key in keys:
            new_node = Node(key)
            node_dict[key] = new_node
        return  node_dict

    def print_graph(self, current, visited={}):
        while current and current.data not in visited:
            print(current.data)
            visited[current.data] = 0
            print self.print_neighbors(current)
            for neighbor in current.neighbors:
                current = neighbor
                return self.print_graph(current, visited)

    def print_neighbors(self, current):
        n_string = " "
        for neighbor in current.neighbors:
            n_string += neighbor.data
            n_string += " "
        return n_string


def create_adj_dict(vert_list):
    adj_dict = {}
    for vertex in vert_list:
        if vertex[0] in adj_dict:
            adj_dict[vertex[0]].append(vertex[1])
        else:
            adj_dict[vertex[0]] = [vertex[1]]
    return adj_dict

def main():
    list_of_vertices = [['A','B'], ['A','E'], ['A','H'],
                        ['B','C'], ['B','H'], ['B','D'],
                        ['C','D'], ['C','G'], ['C','B'],
                        ['D','E'], ['D','C'], ['D','B'],
                        ['E','F'], ['E','D'], ['E','A'],
                        ['F','G'], ['F','E'], ['F','B'],
                        ['G','H'], ['G','F'], ['G','C'],
                        ['H','A'], ['H','G'], ['H','D']]

    adj_dict = create_adj_dict(list_of_vertices)
    print adj_dict
    print sorted(adj_dict.keys())
    graph = Graph()
    graph.create_graph(adj_dict)
    visited = {}
    print graph.print_graph(graph.head, visited)

main()