[演算法導論]拓撲排序 @ Python

標籤：

class Graph:    def __init__(self):        self.V = []class Vertex:    def __init__(self, x):        self.key = x        self.color = ‘white‘        self.d = 10000        self.f = 10000        self.pi = None        self.adj = []        self.next = Noneclass Solution:    def Dfs(self, G):        for u in G.V:            u.color = ‘white‘            u.pi = None        global time        time = 0        for u in G.V:            if u.color == ‘white‘:                self.DfsVisit(G, u)    def DfsVisit(self, G, u):        global time        time = time + 1        u.d = time        u.color = ‘gray‘        for v in u.adj:            if v.color == ‘white‘:                self.DfsVisit(G, v)                v.pi = u        u.color = ‘black‘        time = time + 1        u.f = time    def TopologicalSort(self, G):        LinkedList = Vertex(‘#‘)        self.Dfs(G)        G.V.sort(key=lambda v:v.f)        for v in G.V:            v.next = LinkedList.next            LinkedList.next = v        return LinkedListif __name__ == ‘__main__‘:    undershorts = Vertex(‘undershorts‘)     socks = Vertex(‘socks‘)     pants = Vertex(‘pants‘)     shoes = Vertex(‘shoes‘)     belt = Vertex(‘belt‘)    shirt = Vertex(‘shirt‘)     tie = Vertex(‘tie‘)    jacket = Vertex(‘jacket‘)     watch = Vertex(‘watch‘)    undershorts.adj = [pants, shoes]    socks.adj = [shoes]    pants.adj = [belt, shoes]    shoes.adj = []    belt.adj = [jacket]    shirt.adj = [belt, tie]    tie.adj = [jacket]    jacket.adj = []    watch.adj = []    G = Graph()    G.V = [undershorts,socks,pants,shoes,belt,shirt,tie,jacket,watch]    m = Solution()    Sort_List = m.TopologicalSort(G)    p = Sort_List    while p.next != None:        print p.next.key, p.next.f        p = p.next

 

[演算法導論]拓撲排序 @ Python