力扣刷题记录---利用python实现链表的基本操作

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前言

如何使用python实现链表的基本操作，包括结点的定义，链表的定义，求链表长度，链表是否为空等等一系列函数

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提示：以下是本篇文章正文内容，下面案例可供参考

一、利用python实现链表的基本操作

链表中的节点应该包含数值和指向下一个元素的地址。

1.节点的定义使用类实现：

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

由于python万物皆对象，变量实际上是对象的引用，相当于就保存了对象的地址

1.链表的定义使用类实现：

链表的定义如下，也是使用类实现：

class Single_LinkList():
    def __init__(self,node = None):
        self.head = node

初始化时会自动生成一个空链表，其中head指向None

3.判断是否为空函数实现：

    def is_empty(self):
        """链表是否为空"""
        if self.head == None:
            return True
        else:
            return False

4.链表长度函数实现：

    def length(self):
        """链表长度"""
        len = 0
        cur = self.head
        while cur != None:
            len = len + 1
            cur = cur.next
        return len

5.遍历链表函数实现：

    def travel(self):
        """遍历链表"""
        cur =  self.head
        while cur != None:
            print(cur.elem)
            cur = cur.next

6.头插法函数实现：

    def add(self,item):
        """链表头部进行添加元素"""
        node = Node(item)
        node.next = self.head
        self.head = node

7.尾插法函数实现：

    def append(self,item):
        """链表尾部进行添加元素"""
        node = Node(item)
        cur = self.head
        if self.is_empty():
            self.head = node
        else:
            while cur.next != None:
                cur = cur.next
            cur.next = node
            node.next = None

8.在链表指定位置插入值函数实现：

    def insert(self,pos,item):
        """
        在指定位置上添加元素
        :param pos: 从0开始
        :param item:
        :return:
        """
        node = Node(item)
        count = 0
        cur = self.head
        while cur != None:
            if count == pos - 1:
                node.next = cur.next
                cur.next = node
                break
            cur = cur.next
            count = count + 1

9.删除某一个值函数实现：

    def remove(self,item):
        """删除某一个节点"""
        cur = self.head
        count = 0
        if self.is_empty():
            print("删除失败")
        elif self.head.elem == item:
            self.head = self.head.next
        else:
            while cur.next != None:
                if cur.next.elem == item:
                    cur.next = cur.next.next
                    break
                cur = cur.next

10查看某个节点是否存在函数实现：

    def search(self,item):
        """查看某个节点是否存在"""
        cur = self.head
        while cur != None:
            if cur.elem == item:
                return True
            cur = cur.next
        return False

完整代码如下：

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

class Single_LinkList():
    def __init__(self,node = None):
        self.head = node
    def is_empty(self):
        """链表是否为空"""
        if self.head == None:
            return True
        else:
            return False
    def length(self):
        """链表长度"""
        len = 0
        cur = self.head
        while cur != None:
            len = len + 1
            cur = cur.next
        return len
    def travel(self):
        """遍历链表"""
        cur =  self.head
        while cur != None:
            print(cur.elem)
            cur = cur.next
    def add(self,item):
        """链表头部进行添加元素"""
        node = Node(item)
        node.next = self.head
        self.head = node
    def append(self,item):
        """链表尾部进行添加元素"""
        node = Node(item)
        cur = self.head
        if self.is_empty():
            self.head = node
        else:
            while cur.next != None:
                cur = cur.next
            cur.next = node
            node.next = None
    def insert(self,pos,item):
        """
        在指定位置上添加元素
        :param pos: 从0开始
        :param item:
        :return:
        """
        node = Node(item)
        count = 0
        cur = self.head
        while cur != None:
            if count == pos - 1:
                node.next = cur.next
                cur.next = node
                break
            cur = cur.next
            count = count + 1
    def remove(self,item):
        """删除某一个节点"""
        cur = self.head
        count = 0
        if self.is_empty():
            print("删除失败")
        elif self.head.elem == item:
            self.head = self.head.next
        else:
            while cur.next != None:
                if cur.next.elem == item:
                    cur.next = cur.next.next
                    break
                cur = cur.next
    def search(self,item):
        """查看某个节点是否存在"""
        cur = self.head
        while cur != None:
            if cur.elem == item:
                return True
            cur = cur.next
        return False

测试代码如下：

if __name__ == "__main__":
    Linklist = Single_LinkList()
    print(Linklist.is_empty())
    print(Linklist.length())
    print(Linklist.append(1))
    print(Linklist.is_empty())
    print(Linklist.length())
    print(Linklist.append(2))
    print(Linklist.append(3))
    print(Linklist.append(4))
    print(Linklist.append(5))
    Linklist.add(8)
    Linklist.insert(1,10)
    Linklist.remove(8)
    # Linklist.remove(8)
    Linklist.travel()
    print(Linklist.search(1))

结果如下：