Lab003Task001.py

"""
Реализуйте АТД линейный список
посредством двусвязных списков,
дополнительно предусмотрите операции:
Search(x,L), возвращающую позицию
элемента x в списке, PrintList(L),
печатающую элементы списка в
порядке их расположения.
"""

class Node:

    def __init__(self, label):
        self.label = label
        self.next = None

    def getLabel(self):
        return self.label

    def setLabel(self, label):
        self.label = label

    def getNext(self):
        return self.next

    def setNext(self, next):
        self.next = next


class LinkedList:

    def __init__(self):
        self.first = None
        self.last = None
        self.len_list = 0

    def push(self, label, index):

        if index >= 0:


            node = Node(label)


            if self.empty():
                self.first = node
                self.last = node
            else:

                if index == 0:

                    node.setNext(self.first)
                    self.first = node
                elif index >= self.len_list:

                    self.last.setNext(node)
                    self.last = node
                else:

                    prev_node = self.first
                    curr_node = self.first.getNext()
                    curr_index = 1

                    while curr_node != None:

                        if curr_index == index:

                            node.setNext(curr_node)

                            prev_node.setNext(node)

                        prev_node = curr_node
                        curr_node = curr_node.getNext()
                        curr_index += 1


            self.len_list += 1

    def pop(self, index):

        if not self.empty() and index >= 0 and index < self.len_list:

            flag_remove = False

            if self.first.getNext() == None:

                self.first = None
                self.last = None
                flag_remove = True
            elif index == 0:

                self.first = self.first.getNext()
                flag_remove = True
            else:

                prev_node = self.first
                curr_node = self.first.getNext()
                curr_index = 1

                while curr_node != None:

                    if index == curr_index:
                        # o proximo do anterior aponta para o proximo do nó corrente
                        prev_node.setNext(curr_node.getNext())
                        curr_node.setNext(None)
                        flag_remove = True
                        break

                    prev_node = curr_node
                    curr_node = curr_node.getNext()
                    curr_index +=1

            if flag_remove:
                # atualiza o tamanho da lista
                self.len_list -= 1

    def empty(self):
        if self.first == None:
            return True
        return False

    def length(self, x):
        return self.len_list


    def show(self):

        curr_node = self.first

        while curr_node != None:
            print(curr_node.getLabel(), end=' ')
            curr_node = curr_node.getNext()
        print()

    def search(self, x):

        curr_node = self.len_list

        while curr_node == x:
            print(curr_node.getLabel(), end=' ')
            curr_node = curr_node.getLabel()
            print()



list = LinkedList()

list.push('Marcos', 0)
list.show()
list.push('Maria', 1)
list.show()
list.push('Yankee', 0)
list.show()
list.push('Catarina', 2)
list.show()
list.push('Lilica', 5)
list.show()
list.push('Roberta', 4)
list.show()

print('Tamanho da lista: {}.'.format(list.length()))
list.pop(0)
list.show()
list.pop(2)
list.show()
list.pop(5)
list.show()
print('Tamanho da lista: {}.'.format(list.length()))

list.search(1)