图的深度优先搜索（参考算法导论）

#__author__=lx
#__date__=2011-10-03
#__brief__=DFS

time = 0
d = []
f = []
color = []
p = []

def DFS_VISIT( G, i ):

        color[ i ] = 'gray'
        global time
        time += 1
        d[i] = time
        print i+1

        for v in G[i]:
                if color[v-1] == 'white':
                        p[v-1] = i
                        DFS_VISIT( G, v-1 )

        color[i] = 'black'

def DFS( G ):
        
        for i in range( len(G) ):
                color.append( 'white' )
                p.append( None )
                d.append( 0 )
                f.append( 0 )

        for i in range( len(G) ):
                if color[i] == 'white':
                        DFS_VISIT( G, i )



if __name__ == "__main__":
        l1 = [ 2, 3 ]
        l2 = [ 4, 5, 1 ]
        l3 = [ 6, 7, 1 ]
        l4 = [ 2, 8 ]
        l5 = [ 2, 8 ]
        l6 = [ 3, 7 ]
        l7 = [ 3, 6 ]
        l8 = [ 4, 5 ]

        l = [ l1, l2, l3, l4, l5, l6, l7, l8 ]

        DFS( l )