gistfile1.py

def makeMaps(filename):
    f_in = open(filename,'r')
    g, grev = {}, {}
    print "Loading from: "+str(filename)
    for line in f_in:
        nodes = [int(x) for x in line.split()]
##        print "Total nodes: "+str(nodes)
        vertex = nodes[0]
        neighbors = nodes[1:]
##        print "g[vertex]: "+str(vertex)+" has these neighbors: "+(str(neighbors))
        try:
            g[vertex]+=neighbors
        except KeyError:
            g[vertex]=neighbors
        for n in neighbors:
            try:
                grev[n].append(vertex)
            except KeyError:
                grev[n]=[vertex]
    print "Vertices in dictionary: "+str(len(g))
    print "Vertices in reverse graph: "+str(len(grev))
    f_in.close()
    return g,grev