Python中如何定义链表

灰太狼 2022-05-22 12:51 185阅读 0赞

#!/usr/bin/env python
    #定义一个链表
    class Node:
        '''
        定义节点类
        data:数据
        _next:下一个数据
        '''
        def __init__(self,data,_next = None):
            self.data = data
            self._next = _next
        def __repr__(self):
            '''
            用来定义Node的字节输出
            '''
            return str(self.data)
    class ChainTable(Node):
        '''
        定义链表
        '''
        def __init__(self):
            self.head = None
            self.length = 0
    
        def isEmpty(self):
            return (self.length == 0)
            
        def add(self,dataOrNode):
            item = None
            if isinstance(dataOrNode,Node):
                item = dataOrNode
            else:
                item = Node(dataOrNode)
            if not self.head: #若链表的头为空
                self.head = item
                self.length += 1
            else:
                node = self.head
                while node._next: #当有节点时，新增下一个节点
                    node = node._next
                node._next = item
                self.length += 1
    
        def delete(self,index):
            if self.isEmpty():
                print("链表是空的")
                return
            if index < 0 or index >= self.length:
                print("超出索引长度")
                return
    
            #删除第一个节点
            if index == 0:
                self.head = self.head._next
                self.length -= 1
                return
    
            #prev为保存前导节点
            #node为保存当前节点
            #当j与index相等时就
            #相当于找到要删除的节点
            j = 0
            node = self.head
            prev = self.head
            while node._next and j<index:
                prev = node
                node = node._next
                j += 1
            if j == index:#找到节点后将下一个节点覆盖到本节点
                prev._next = node._next
                self.length -= 1
    
        def update(self,index,data):
            if self.isEmpty() or index < 0 or index>=self.length:
                print('超出索引长度')
                return 
            j = 0
            node = self.head
            while node._next and j <index:
                node = node._next
                j +=1
            if j == index:
                node.data = data
        #查找一个节点
        def getItem(self,index):
            if self.isEmpty() or index<0 or index >= self.length:
                print('超出索引长度')
                return 
            j = 0
            node = self.head
            while node._next and j<index:
                node = node._next
                j +=1
            return node.data
         
         #从头到尾打印链表
        def print_chain(self):
            if self.isEmpty():
                print('链表为空')
            num = []
            node = self.head
            while node:
                num.append(node)
                node = node._next
            return num
        #查找一个节点的索引
        def getIndex(self,data):
            j = 0
            if self.isEmpty():
                print('链表为空')
                return
            node = self.head
            while node:
                if node.data == data:
                    return j
                node = node._next
                j += 1
            if j == self.length:
                print("%s not found"%str(data))
                return
        def insert(self,index,dataOrNode):
            if self.isEmpty():
                print('链表为空')
                return
            if index < 0 or index >= self.length:
                print('超出索引长度')
                return
            item = None
            if isinstance(dataOrNode,Node):
                item = dataOrNode
            else:
                item = Node(dataOrNode)
            if index == 0:
                item._next = self.head
                self.head = item
                self.length += 1
                return
            j = 0
            node = self.head
            prev = self.head
            while node._next and j < index:
                prev = node
                node = node._next
                j += 1
            if j == index:
                item._next = node
                prev._next = item
                self.length += 1
    
        def clear(self):
            self.head = None
            self.length = 0
    
        def __repr__(self):
            if self.isEmpty():
                return "链表为空"
            node = self.head
            nlist = ''
            while node:
                nlist += str(node.data)+' '
                node = node._next
            return nlist
        def __getitem__(self,ind):
            if self.isEmpty() or ind <0 or ind>=self.length:
                print("超出索引长度")
                return
            return self.getItem(ind)
        def __setitem__(self,ind,val):
            if self.isEmpty() or ind<0 or ind>=self.length:
                print("超出索引长度")
                return
            self.update(ind,val)
        def __len__(self):
            return self.length
    chainTable = ChainTable()
    for i in range(10):
        chainTable.add(i)
    print(chainTable.getIndex(1))
    print(chainTable.print_chain())