LinkedList 예제

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


class LinkedList:
    def __init__(self):
        self.head = None
        self.size = 0

    def append(self, data):
        if self.head is None:
            self.head = Node(data)
        else:
            node = self.head
            while node.next:
                node = node.next
            node.next = Node(data)

        self.size += 1

    def print_list(self):
        p = self.head
        if p is not None:
            while p:
                if p.next is not None:
                    print(p.data, '-> ', end='')
                else:
                    print(p.data)
                p = p.next
        else:
            print("null")

    def deleteN(self, k):
        p1 = p2 = self.head

        if k > self.size:
            print("size error")
            return 0
        elif k is self.size:
            k -= 1
            if k != 0:
                for i in range(k):
                    p2 = p2.next
                if p2 is None:
                    return None
            while p2.next is not None:
                p2 = p2.next
                p1 = p1.next
            current = p1
            self.head = current.next
        else:
            if k != 0:
                for i in range(k):
                    p2 = p2.next
                if p2 is None:
                    return None
            while p2.next is not None:
                p2 = p2.next
                p1 = p1.next
            p1.next = p1.next.next


if __name__ == '__main__':
    node = LinkedList()
    node.append(1)
    node.append(2)
    node.append(3)
    node.append(4)
    node.append(5)
    node.print_list()
    print("N =", 2)
    node.deleteN(2)
    node.print_list()
    print("------------------------------")

    node2 = LinkedList()
    node2.append(1)
    node2.append(2)
    node2.append(3)
    node2.print_list()
    print("N =", 3)
    node2.deleteN(3)
    node2.print_list()
    print("------------------------------")

    node3 = LinkedList()
    node3.append(1)
    node3.print_list()
    print("N =", 1)
    node3.deleteN(1)
    node3.print_list()