python实现单链表的建立、访问和排序

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第一个比较完整的python程序，排序效率不是很好，待改进！

采用类的方式实现，包含两个文件

list2：定义listNode类及createList、scanList和sortList方法

test2：对listNode类的调用

class listNode:    def __init__(self,x):        self.val = x        self.next  = None            def createList(self,a):        if a is None:           print 'no elements'           return        head=listNode(a[0])        p=head        i=1        n=len(a)        while i<n:            t=listNode(a[i])            p.next=t            p=t            i=i+1        return head    def scanList(self,head):       if head is None:          print "no elements"          return       print head.val       while head.next:             p=head.next             print p.val             head=p                 def sortList(self, head):        if head is None or head.next is None:            return head        mid = (head.val + head.next.val) / 2        if head.val > head.next.val:            lhead, rhead = head.next, head        else:            lhead, rhead = head, head.next        lit, rit = lhead, rhead        it = head.next.next               while it is not None:            if it.val > mid:                rit.next = it                rit = it                            else:                lit.next = it                lit = it             it = it.next        lit.next, rit.next = None, None        lhead = self.sortList(lhead)        rhead = self.sortList(rhead)        it = lhead        while it.next is not None:            it = it.next        it.next = rhead        return lhead

test2.py

import list2l=list2.listNode(0)a=[2,5,9,3,6,1,0,7,4,19]head=l.createList(a)print 'old list:'l.scanList(head)newhead=l.sortList(head)print 'sorted list:'l.scanList(newhead)

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