python单链表的基本操作

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


# 头插法  无头节点
class OpeareLink:
    def __init__(self):
        self.current_node = None

    def add(self, data):
        node = Node(data)
        node.next = self.current_node
        # 指针始终指向当前节点
        self.current_node = node

    def print_node(self):
        cur_node = self.current_node
        while cur_node:
            print(cur_node.data)
            cur_node = cur_node.next

    def is_empty(self):
        return self.current_node is None

    def get_length(self):
        cnt = 0
        cur = self.current_node
        while cur:
            cnt += 1
            cur = cur.next
        return cnt

    def insert_node(self, data, index):
        cur = self.current_node
        if index <= 0 or cur is None:
            self.add(data)
        else:
            cnt = 0
            while cur.next:
                if cnt == index:
                    break
                cnt += 1
                cur = cur.next
            node = Node(data)
            node.next = cur.next
            cur.next = node

    def delete_node(self, index):
        if self.is_empty() or index <= 0:
            return

        if index == 1:
            self.current_node = self.current_node.next
        else:
            cnt = 2
            pre_node = self.current_node
            cur = pre_node.next
            while cur:
                if index == cnt:
                    break
                pre_node = cur
                cur = pre_node.next
                cnt += 1
            # index大于链表的情况
            if cur is None:
                pre_node.next = None
                return
            pre_node.next = cur.next


# 尾插法   有头节点
class OperateLink1:
    def __init__(self):
        # 定义一个头节点，当前指针位置在头节点处
        self.head = Node(0)
        self.current_node = self.head

    def add(self, data):
        # 新建节点
        node = Node(data)
        # 当前节点指向新建节点
        self.current_node.next = node
        # 将指针移动到新建的节点上
        self.current_node = node

    def print_node(self):
        cur_node = self.head.next
        while cur_node:
            print(cur_node.data)
            cur_node = cur_node.next


if __name__ == "__main__":
    data_list = [1, 6, 7, 9, 2]

    # 头插法
    test = OpeareLink()
    for i in data_list:
        test.add(i)
    # current_node = test.current_node
    # while current_node:
    #     print(current_node.data)
    #     current_node = current_node.next
    # test.print_node()
    # print(test.is_empty())
    # test.insert_node(3, 4)
    # test.print_node()
    test.delete_node(6)
    test.print_node()
    # 尾插法
    # test1 = OperateLink1()
    # for i in data_list:
    #     test1.add(i)
    # test1.print_node()