链表

链表实现的基本构造块是节点。每个节点对象必须至少保存两个信息。
首先，节点必须包含列表项本身。我们将这个称为节点的数据字段。此外，每个节点必须保存对下一个节点的引用。

无序链表

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class Node():
    def __init__(self,initdata):
        self.data = initdata
        self.next = None

    def getData(self):
        return self.data

    def getNext(self):
        return self.next

    def setData(self,newdata):
        self.data = newdata

    def setNext(self,newnext):
        self.next = newnext
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tmp=Node(99)
tmp.getData()
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99
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class UnorderedList():

    def __init__(self):
        self.head = None
        
    def isEmpty(self):
        return self.head == None

    def add(self,item):
        temp = Node(item)
        temp.setNext(self.head)
        self.head = temp
    
    def size(self):
        current = self.head
        count = 0
        while current != None:
            count = count + 1
            current = current.getNext()
        return count
    
    def search(self,item):
        current = self.head
        found = False
        while current != None and not found:
            if current.getData() == item:
                found = True
            else:
                current = current.getNext()

        return found

    def remove(self,item):
        current=self.head
        previous=None
        found = False
        while current != None and not found:
            if current.getData() == item:
                found = True
            else:
                previous=current
                current= current.getNext()
        if previous == None:
            self.head = current.getNext()
        else:
            previous.setNext(current.getNext())
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mylist = UnorderedList()
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mylist.add(13)
mylist.add(23)
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mylist.size()
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mylist.search(13)
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True
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mylist.remove(23)
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mylist.search(23)
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False

有序列表

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class OrderedList:
    def __init__(self):
        self.head = None
               
    def isEmpty(self):
        return self.head == None

    def add(self,item):
        temp = Node(item)
        temp.setNext(self.head)
        self.head = temp
    
    def size(self):
        current = self.head
        count = 0
        while current != None:
            count = count + 1
            current = current.getNext()
        return count
        
        
    def search(self,item):
        current = self.head
        found = False
        stop = False
        while current != None and not found and not stop:
            if current.getData() == item:
                found = True
            else:
                if current.getData() > item:
                    stop = True
                else:
                    current = current.getNext()

        return found
    
    def add(self,item):
        current = self.head
        previous = None
        stop = False
        while current != None and not stop:
            if current.getData() > item:
                stop = True
            else:
                previous = current
                current = current.getNext()

        temp = Node(item)
        if previous == None:
            temp.setNext(self.head)
            self.head = temp
        else:
            temp.setNext(current)
            previous.setNext(temp)