cviceni 03

class Node:

    def __init__(self, data:any):

        self.data = data

        self.next = None

    def __str__(self):

        return str(self.data)

class LinkedList:

    def __init__(self) -> None:

        self.head = None

    def add_at_begin(self, data):

        new_node = Node(data)

        new_node.next = self.head

        self.head = new_node

    def __str__(self) -> str:

        current_node = self.head

        result = ''

        while current_node != None:

            result += str(current_node.data) + ' -> '

            current_node = current_node.next

        return result + 'None'

    def remove_at_begin(self) -> any:

        if self.head == None:

            return None

        data = self.head.data

        self.head = self.head.next

        return data

    def find(self, index:int) -> Node:

        if self.head == None:

            return None

        if index == 0:

            return None

        pos = 0

        current_node = self.head

        while current_node and pos + 1 < index:

            pos += 1

            current_node = current_node.next

        return current_node

    def remove_at_index(self, index:int) -> any:

        current_node = self.find(index)

        if index==0:

            return self.remove_at_begin()

        if current_node==None or current_node.next == None:

            return None

        data = current_node.next.data

        current_node.next = current_node.next.next

        return data

ll = LinkedList()

ll.add_at_begin(1)

ll.add_at_begin("Ahoj")

ll.add_at_begin(3)

print(ll)

print(ll.find(0))

print(ll.find(1))

print(ll.find(2))

print(ll.remove_at_index(0))

print(ll)

 No newline at end of file

class Node:

    def __init__(self, data) -> None:

        self.data = data

        self.next = None

    def __str__(self) -> str:

        return str(self.data)

class LinkedList:

    def __init__(self) -> None:

        self.head = None

    def add_at_begin(self, data) -> None:

        new_node = Node(data)

        new_node.next = self.head

        self.head = new_node

    # def __str__(self) -> str:

    #     current_node = self.head

    #     result = '[ '

    #     while current_node!=None:

    #         result = result + str(current_node) + ' -> '

    #         current_node = current_node.next

    #     return result + 'None ]'

    def __str__(self) -> str:

        result = '[ '

        for x in self:

            result += str(x) + ' -> '

        return result + 'None ]'

    def remove_at_begin(self) -> any:

        if not self.head:   #if self.head == None

            return None

        data = self.head.data

        self.head = self.head.next

        return data

    def find(self, index:int) -> tuple[Node, Node]:

        if index<0:

            return None, None

        if not self.head:

            return None, None

        pos = 0

        current_node = self.head

        prev_node = None

        while current_node and pos<index:

            pos += 1

            prev_node = current_node

            current_node = current_node.next

        return prev_node, current_node

    def remove_at_index(self, index:int) -> any:

        prev, current = self.find(index)

        if current==None:

            return None

        if prev==None:

            return self.remove_at_begin()

        data = current.data

        prev.next = current.next

        return data

    def insert_at_index(self, data, index) -> None:

        prev, current = self.find(index)

        if prev and not current:

            new_node = Node(data)

            prev.next = new_node

            return None

        if current==None:

            return None

        if prev==None:

            self.add_at_begin(data)

            return None

        new_node = Node(data)

        new_node.next = current

        prev.next = new_node

    def __iter__(self):

        current_node = self.head

        while current_node:

            yield current_node

            current_node = current_node.next

ll = LinkedList()

ll.add_at_begin(10)

ll.add_at_begin("Ahoj")

ll.add_at_begin(1.5)

print(ll)

ll.insert_at_index("ABC", 3)

print(ll)

for x in ll:

    print(x)