Use Python 3

Problem: The goal of this exercise is to create a doubly linked list. You have to use the file d_linked_node.py and the d_linked_list.py. The d_linked_node is ready and the d_linked_list you will have to complete. The methods: add(self, item) Adds a new item to the front of the list remove(self,item) Removes the first element that is equal to item from the list. If that doesnt exist it changes nothing

append(self, item) Adds item to the end of the list

insert(self, pos, item) Add item to the given position in the list (i.e if pos is 0 then item goes to the beginning of the list)

pop1(self) Removes and returns the last item in the list pop(self, pos) Removes and returns the item in the given position

search_larger(self, item) Returns the position of the first item that is larger than item, -1 if there is no item larger get_size(self) Returns the size of the list

get_item(self, pos) Returns the item that exists at pos, Raises exception if pos doesnt exist pos can be negative which means the position from the end of the list. (-1 is the last item, -2 the second from last etc.)

__str__(self) Returns a string that is the elements of the DLinkedList with spaces in between

Thank you!!

d_linked_node.py class d_linked_node: def __init__(self, initData, initNext, initPrevious): # constructs a new node and initializes it to contain # the given object (initData) and links to the given next # and previous nodes. self.__data = initData self.__next = initNext self.__previous = initPrevious if (initPrevious != None): initPrevious.__next = self if (initNext != None): initNext.__previous = self def getData(self): return self.__data def getNext(self): return self.__next def getPrevious(self): return self.__previous def setData(self, newData): self.__data = newData def setNext(self, newNext): self.__next= newNext def setPrevious(self, newPrevious): self.__previous= newPrevious

d_linked_list.py from d_linked_node import d_linked_node

class d_linked_list: def __init__(self): self.__head=None self.__tail=None self.__size=0

def search(self, item): current = self.__head found = False while current != None and not found: if current.getData() == item: found= True else: current = current.getNext() return found def index(self, item): current = self.__head found = False index = 0 while current != None and not found: if current.getData() == item: found= True else: current = current.getNext() index = index + 1 if not found: index = -1 return index def add(self, item): # TODO: def remove(self, item): # TODO: def append(self, item): # TODO: def insert(self, pos, item): # TODO: def pop1(self): # TODO: def pop(self, pos): # TODO: def search_larger(self, item): # TODO: def get_size(self): # TODO: def get_item(self, pos): # TODO: def __str__(self): # TODO: def test():

linked_list = d_linked_list() is_pass = (linked_list.get_size() == 0) assert is_pass == True, "fail the test" linked_list.add("World") linked_list.add("Hello") is_pass = (str(linked_list) == "Hello World") assert is_pass == True, "fail the test" is_pass = (linked_list.get_size() == 2) assert is_pass == True, "fail the test" is_pass = (linked_list.get_item(0) == "Hello") assert is_pass == True, "fail the test" is_pass = (linked_list.get_item(1) == "World") assert is_pass == True, "fail the test" is_pass = (linked_list.get_item(0) == "Hello" and linked_list.get_size() == 2) assert is_pass == True, "fail the test" is_pass = (linked_list.pop(1) == "World") assert is_pass == True, "fail the test" is_pass = (linked_list.pop1() == "Hello") assert is_pass == True, "fail the test" is_pass = (linked_list.get_size() == 0) assert is_pass == True, "fail the test" int_list2 = d_linked_list() for i in range(0, 10): int_list2.add(i) int_list2.remove(1) int_list2.remove(3) int_list2.remove(2) int_list2.remove(0) is_pass = (str(int_list2) == "9 8 7 6 5 4") assert is_pass == True, "fail the test" for i in range(11, 13): int_list2.append(i) is_pass = (str(int_list2) == "9 8 7 6 5 4 11 12") assert is_pass == True, "fail the test" for i in range(21, 23): int_list2.insert(0,i) is_pass = (str(int_list2) == "22 21 9 8 7 6 5 4 11 12") assert is_pass == True, "fail the test" is_pass = (int_list2.get_size() == 10) assert is_pass == True, "fail the test" int_list = d_linked_list() is_pass = (int_list.get_size() == 0) assert is_pass == True, "fail the test" for i in range(0, 1000): int_list.append(i) correctOrder = True is_pass = (int_list.get_size() == 1000) assert is_pass == True, "fail the test" for i in range(0, 200): if int_list.pop1() != 999 - i: correctOrder = False is_pass = correctOrder assert is_pass == True, "fail the test" is_pass = (int_list.search_larger(200) == 201) assert is_pass == True, "fail the test" int_list.insert(7,801) is_pass = (int_list.search_larger(800) == 7) assert is_pass == True, "fail the test" is_pass = (int_list.get_item(-1) == 799) assert is_pass == True, "fail the test" is_pass = (int_list.get_item(-4) == 796) assert is_pass == True, "fail the test" if is_pass == True: print ("=========== Congratulations! Your have finished exercise 1! ============") if __name__ == '__main__': test()