Python链表与子串元素朴素匹配和链表元素替换

 朴素匹配可以换成KMP算法，这样的话，时间复杂度能达到线性

 主要考虑是建立新的链表子串替换原链表中间的匹配项。不多说了，直接上代码

 

class Node:

    def__init__(self,element=None,next_=None,prev=None):

        self._element=element

        self._next=next_

        self._prev=prev

class StrList:

    def__init__(self,string1):

        self._head=None

        self._rear=None

        self._len=0

        i=0

        n=len(string1)

        while i<n:

            ifself._head is None:

                p=Node(string1[0])

                self._head=p

                self._rear=p

                self._len+=1

            else:

                p=Node(string1[i])

                p._prev=self._rear

                self._rear._next=p

                self._rear=p

                self._len+=1

            i +=1

    defprintall(self):

        p=self._head

        while pis notNone:

            print(p._element)

            p=p._next

    defget_len(self):

        returnself._len

    defmatch(self,patternstr):

        n=len(patternstr)

        i,j=0,0

        p=self._head

        while i<nand p is notNone:

            if patternstr[i]==p._element:

                i+=1

                j+=1

                p=p._next

            else:

                j=j-i+1

                while i>0:

                    p=p._prev

                    i-=1

                p=p._next

                i=0

        if i==n:

            return j-i

        return-1

    defreplace(self,patternstr,restr):

        ifself.match(patternstr)==-1:

            return"No match"

        q=self._head

        t=self._head

        i=self.match(patternstr)

        j=0

        n=len(restr)

        length=i+len(patternstr)

        shead=None

        srear=None

        while i>0:         #set break point of first match point

            t=t._next

            i-=1

        while length>0:    #set break point of second match point

            q=q._next

            length-=1

        while j<n:         #establish a new link string independently

            if sheadis None:

                shead=Node(restr[j])

                srear=shead

            else:

                s=Node(restr[j])

                s._prev=srear

                srear._next=s

                srear=s

            j+=1

        if t._previs None:  #attach new link string to two break points

            self._head=shead

            srear._next=q

            q._prev=srear

        elif qis None:

            self._rear=srear

            t._prev._next=shead

            shead._prev=t._prev

        else:

            t._prev._next=shead

            shead._prev=t._prev

            srear._next=q

            q._prev=srear