def addition(llist1,llist2):
curr1 = llist1.head
curr2 = llist2.head
myList = LinkedList()
carry = 0
temp = None
while(curr1 is not None or curr2 is not None):
lvalue= curr1.data if curr1 else 0
rvalue= curr2.data if curr2 else 0
val = lvalue + rvalue + carry
carry = 1 if val >10 else 0
val = val % 10
newNode = Node(val)
if myList.head is None:
myList.head = newNode
temp = myList.head
else:
temp.next = newNode
temp = temp.next
if curr1 is not None:
curr1 = curr1.next
if curr2 is not None:
curr2 = curr2.next
if carry>0:
temp.next = Node(carry)
return myList
def test_in_filter_preserves_front_and_back_if_needed(self):
ll = LinkedList()
item1 = ll.add_to_front(123, 123123)
item2 = ll.add_to_front(234234, 92834923)
ll.in_filter(None)
assert ll.front == item2
assert ll.back == item1
def test_in_filter_None_equal_to_identity(self):
ll = LinkedList()
item1 = ll.add_to_front(123, 8907067)
ll.in_filter(None)
assert item1.key == ll.front.key
assert item1.value == ll.front.value
assert ll.length == 1
def test_prev_from_front_is_none(self):
'''Item at the front has None as prev pointer'''
ll = LinkedList()
ll.add_to_front(0, 98)
assert ll.front.prev == None
ll.add_to_front(123, 98)
assert ll.front.prev == None
def test_last_item_point_to_none(self):
'''Item at the back has None as next pointer'''
ll = LinkedList()
ll.add_to_back(0, 23)
assert ll.back.next == None
ll.add_to_back(123, 234)
assert ll.back.next == None
class AnimalShelter:
def __init__(self):
self.dogs = LinkedList()
self.cats = LinkedList()
self.counter = 0
def enqueue(self, animal):
if animal.species == 'dog':
self.dogs.add((animal, self.counter))
elif animal.species == 'cat':
self.cats.add((animal, self.counter))
else:
raise Exception("Unsupported animal type.")
self.counter += 1
def dequeue_dog(self):
return self.dogs.pop()
def dequeue_cat(self):
return self.cat.pop()
def dequeue_any(self):
dog = self.dogs.head
cat = self.cats.head
if dog is None:
return cat
if cat is None:
return dog
if dog.value[1] > cat.value[1]:
return cat
else:
return dog
def test_insert_two():
l_list = LinkedList()
l_list.insert("David")
l_list.insert("Thomas")
assert l_list.head.get_data() == "Thomas"
head_next = l_list.head.get_next()
assert head_next.get_data() == "David"
def reverse_in_place(ll):
"""
Steps:
a -> b -> c
<- a b -> c * When we are changing b we need references to a and c
<- a <- b c
<- a <- b <- c
"""
if ll.length < 2:
return ll
previous = ll.head
current = previous.next
later = current.next
previous.next = None
while True:
current.next = previous
previous = current
current = later
if current is not None:
later = current.next
else:
break
reverse_list = LinkedList()
reverse_list.head = previous
return reverse_list
def create_random_list(self):
random_list = LinkedList()
x = random.randint(1, 200)
for i in range(0, x):
value = random.randint(1, 10000)
random_list.append(value)
return random_list
def test_reverse_single(self):
ll = LinkedList(358)
self.assertEqual(358, ll.peek())
self.assertEqual(1, len(ll))
ll.reverse()
self.assertEqual(358, ll.peek())
self.assertEqual(1, len(ll))
def test_insert_after(self):
llist = LinkedList()
for i in xrange(10):
llist.push_back(i)
for item in llist:
if item.value % 2 == 0:
llist.insert_after(item, item.value - 1)
self.assertEqual([0,-1,1,2,1,3,4,3,5,6,5,7,8,7,9], [node.value for node in llist])
def test_add_back_multiple_equal_items(self):
'''Adding the same item to the back of the list multiple times creates
different linked list objects with the same item'''
ll = LinkedList()
ll.add_to_back(12)
ll.add_to_back(12)
assert ll.back.key == ll.back.prev.key
assert ll.back != ll.back.prev
def main():
test = LinkedList()
for i in range(20):
test.add(i)
print(test)
print('Find the node before last', findKelementh(test, 2))
print('Find the last node', findKelementh(test, 1))
print('Finding 12th to last Node: ', findKelementh(test, 12))
def test_remove_updates_head_if_necessary(self):
'''Removing head, updates head'''
ll = LinkedList()
item1 = ll.add_to_front(1234)
item2 = ll.add_to_front(list())
assert ll.front == item2
ll.remove(item2)
assert ll.front == item1
def test_removed_item_has_no_parent(self):
'''Removing an item also removes any references from the item to the
list'''
ll = LinkedList()
litem = ll.add_to_back(list())
assert litem.parent()
ll.remove(litem)
assert litem.parent == None
def test_remove_all_items_deletes_front_and_back(self):
ll = LinkedList()
item1 = ll.add_to_back("lkjh")
item2 = ll.add_to_back([1,2,3])
ll.remove(item2)
ll.remove(item1)
assert ll.front == None
assert ll.back == None
def test_remove_updates_back_if_necessary(self):
'''Removing back updates back'''
ll = LinkedList()
item1 = ll.add_to_back(123)
item2 = ll.add_to_back("lkj")
assert ll.back == item2
ll.remove(item2)
assert ll.back == item1
def test_map_filter_equal_to_identity(self):
ll = LinkedList()
item1 = ll.add_to_front(123, 8907067)
ll2 = ll.filter(None)
item2 = ll2.front
assert item1.key == item2.key
assert item1.value == item2.value
assert ll.length == ll2.length
def test_insert_before_return_new_item(self):
ll = LinkedList()
item1 = ll.add_to_front(5151, 91951)
key = 123
value = [1,2,3]
item2 = ll.insert_before(item1, key, value)
assert item2.key == key
assert item2.value == value
def test_swap_preserves_length(self):
ll = LinkedList()
item1 = ll.add_to_front(5151, 91951)
assert ll.length == 1
item2 = ll.add_to_front(235151, 91951)
assert ll.length == 2
ll.swap(item1, item2)
assert ll.length == 2
def test_filter_creates_new_items(self):
ll = LinkedList()
item1 = ll.add_to_front(12, 3534536)
ll2 = ll.filter(None)
item2 = ll2.front
assert item1 != item2
assert item1.key == item2.key
assert item2.value == item2.value
def test_add_back_appends_item(self):
'''Adding to the back of the list multiple times does not remove items.
Instead the list is appended with the new item'''
ll = LinkedList()
ll.add_to_back(12, 345)
ll.add_to_back(14, 34)
assert ll.back.key == 14
assert ll.back.prev.key == 12
def test_add_front_prepends_item(self):
'''Adding to the front of the list multiple times does not remove items.
Instead the list is prepended with the new item'''
ll = LinkedList()
ll.add_to_front(12, 54)
ll.add_to_front(14, 98)
assert ll.front.key == 14
assert ll.front.next.key == 12
def test_add_front_multiple_equal_items(self):
'''Adding the same item to the front of the list multiple times creates
different linked list objects with the same item'''
ll = LinkedList()
ll.add_to_front(12)
ll.add_to_front(12)
assert ll.front.key == ll.front.next.key
assert ll.front != ll.front.next
def test_insert_before(self):
llist = LinkedList()
for i in xrange(10):
llist.push_back(i)
for item in llist:
if item.value % 2 == 0:
llist.insert_before(item, item.value)
self.assertEqual([0,0,1,2,2,3,4,4,5,6,6,7,8,8,9], [node.value for node in llist])
def main():
ll = LinkedList()
data = [char for char in 'FOLLOW UP']
for char in data[::-1]:
node = Node(char)
ll.insert(node)
remove_duplicates(ll.head)
print "%s" % ll == "%s" % ['F', 'O', 'L', 'W', ' ', 'U', 'P']
def main():
ll = LinkedList()
data = [char for char in '123456789']
for char in data[::-1]:
node = Node(char)
ll.insert(node)
print ll
print ll.size()
print kth_tolast(ll.head, 5).val == '123456789'[-5]
def test_find_last_finds_last(self):
ll = LinkedList()
key = 123
value1 = 441
value2 = "sdsfgg"
ll.add_to_front(key, value1)
ll.add_to_front(key, value2)
item = ll.find_last(key)
assert item.value == value1
def test_add_to_front_prev(self):
'''Add to front places previous front after the new front'''
ll = LinkedList()
key1 = 123
key2 = 1233
ll.add_to_front(key1)
ll.add_to_front(key2)
assert ll.front.next.key == key1
assert ll.front.next.prev.key == key2
class Stack(object):
def __init__(self,top=None):
self.ll = LinkedList(top)
def push(self, new_element):
self.ll.insert_first(new_element)
def pop(self):
return self.ll.delete_first()
def __init__(self):
self.items = LinkedList()
"<-------------------Sweepstakes---------------------------------------->"
)
test3 = Sweepstakes()
test3.sweepstatkes_signup("sixth", "six")
test3.find_a_winner()
print(
"<-------------------Family Dictionary---------------------------------------->"
)
test4 = Familymembers()
test4.print_family()
print(
"<-------------------LinkedList---------------------------------------->"
)
linked_list = LinkedList()
linked_list.append_node(55)
linked_list.append_node(60)
linked_list.append_node(65)
linked_list.append_node(70)
linked_list.append_node(75)
linked_list.append_node(80)
linked_list.add_to_beginning(30)
linked_list.contains_node()
print(
"<-------------------BinaryTree---------------------------------------->"
)
tree = Binarytree()
tree.add_to_tree(50)
def set_up(l1, l2):
intersecting_node = Node(5)
intersecting_node.next = Node(6)
intersecting_node.next.next = Node(7)
l1tail = l1.head
l2tail = l2.head
while l1tail.next is not None:
l1tail = l1tail.next
l1tail.next = intersecting_node
while l2tail.next is not None:
l2tail = l2tail.next
l2tail.next = intersecting_node
l1 = LinkedList()
l2 = LinkedList()
l1.add_multiple([1, 2, 3, 4])
l2.add_multiple([9, 2])
set_up(l1, l2)
print("The intersecting node contains the value:",
intersection(l1, l2)) # This returns the intersecting node but the
# __str__ function forces the return of the node value
class LinkedStack(object):
def __init__(self, iterable=None):
"""Initialize this stack and push the given items, if any."""
# Initialize a new linked list to store the items
self.list = LinkedList()
if iterable is not None:
for item in iterable:
self.push(item)
def __repr__(self):
"""Return a string representation of this stack."""
return 'Stack({} items, top={})'.format(self.length(), self.peek())
def is_empty(self):
"""Return True if this stack is empty, or False otherwise."""
# TODO: Check if empty
return self.list.is_empty()
def length(self):
"""Return the number of items in this stack."""
# TODO: Count number of items
return self.list.length()
def push(self, item):
"""Insert the given item on the top of this stack.
Running time: O(???) – Why? [TODO]
the time complexity of this function is O(1) constant time because for a linked list
appending an item takes just a few actions that are not reliant on the number of entries
in the linked list
"""
# TODO: Push given item
self.list.prepend(item)
def peek(self):
"""Return the item on the top of this stack without removing it,
or None if this stack is empty.
this function takes constant time O(1) because accessing the head node of a linked
list takes constant time. Traversing a linked list takes O(n) but because the target node is
always the head node then it takes constant time
"""
# TODO: Return top item, if any
if self.is_empty():
return None
else:
return self.list.head.data
def pop(self):
"""Remove and return the item on the top of this stack,
or raise ValueError if this stack is empty.
Running time: O(???) – Why? [TODO]
This function takes O(n) time every time because the linked list's
delete function is called to delete the node but that means that
function call will traverse the entire linked list until it gets to
the tail. The LL delete function's worst case running time is O(n) and
the way it is being called here means it will always hit the worst
case running time
"""
# TODO: Remove and return top item, if any
if self.list.head:
top_data = self.list.head.data
self.list.delete(top_data)
return top_data
else:
raise ValueError("stack empty")
def test_find(self):
ll = LinkedList(['A', 'B', 'C'])
assert ll.find(lambda item: item == 'B') == 'B' # Match equality
assert ll.find(lambda item: item < 'B') == 'A' # Match less than
assert ll.find(lambda item: item > 'B') == 'C' # Match greater than
assert ll.find(lambda item: item == 'X') is None # No matching item
def test_delete_with_3_items(self):
ll = LinkedList(['A', 'B', 'C'])
assert ll.head.data == 'A' # First item
assert ll.tail.data == 'C' # Last item
ll.delete('A')
assert ll.head.data == 'B' # New head
assert ll.tail.data == 'C' # Unchanged
ll.delete('C')
assert ll.head.data == 'B' # Unchanged
assert ll.tail.data == 'B' # New tail
ll.delete('B')
assert ll.head is None # No head
assert ll.tail is None # No tail
# Delete should raise error if item was already deleted
with self.assertRaises(ValueError):
ll.delete('A') # Item no longer in list
with self.assertRaises(ValueError):
ll.delete('B') # Item no longer in list
with self.assertRaises(ValueError):
ll.delete('C') # Item no longer in list
def test_find(self):
ll = LinkedList(['A', 'B', 'C'])
assert ll.find('B') == 'B' # Match equality
assert ll.find('C') == 'C' # Match equality
assert ll.find('X') is None # No matching item
def test_delete_with_5_items(self):
ll = LinkedList(['A', 'B', 'C', 'D', 'E'])
assert ll.head.data == 'A' # First item
assert ll.tail.data == 'E' # Last item
ll.delete('A')
assert ll.head.data == 'B' # New head
assert ll.tail.data == 'E' # Unchanged
ll.delete('E')
assert ll.head.data == 'B' # Unchanged
assert ll.tail.data == 'D' # New tail
ll.delete('C')
assert ll.head.data == 'B' # Unchanged
assert ll.tail.data == 'D' # Unchanged
ll.delete('D')
assert ll.head.data == 'B' # Unchanged
assert ll.tail.data == 'B' # New tail
ll.delete('B')
assert ll.head is None # No head
assert ll.tail is None # No tail
def test_init(self):
ll = LinkedList()
# Initializer should add instance properties
assert ll.head is None # First node
assert ll.tail is None # Last node
def test_length_after_delete(self):
ll = LinkedList(['A', 'B', 'C', 'D', 'E'])
assert ll.length() == 5
# Delete should decrease length
ll.delete('A')
assert ll.length() == 4
ll.delete('E')
assert ll.length() == 3
ll.delete('C')
assert ll.length() == 2
ll.delete('D')
assert ll.length() == 1
ll.delete('B')
assert ll.length() == 0
def __init__(self, init_size=8):
"""Initialize this hash table with the given initial size."""
self.buckets = [LinkedList() for i in range(init_size)]
self.size = 0 # Number of key-value entries
def __init__(self, init_size=8):
"""Initialize this hash table with the given initial size."""
# Create a new list (used as fixed-size array) of empty linked lists
self.buckets = [LinkedList() for _ in range(init_size)]
def test_list_creation(self):
linked_list = LinkedList()
self.assertIsNone(linked_list.get_root())
class Queue():
"""A queue. FIFO.
Operations: enqueue(item), dequeue(), peek(), is_empty()
Make a queue:
>>> karaoke_playlist = Queue()
Anything in the queue?
>>> karaoke_playlist.is_empty()
True
If there's nothing in the karaoke queue, how can we sing like crazy
people? Let's add songs.
>>> karaoke_playlist.enqueue("Try Everything -- Shakira")
>>> karaoke_playlist.enqueue("Sing -- Pentatonix")
>>> karaoke_playlist.enqueue("Best Day of My Life -- American Authors")
Anything in the queue now?
>>> karaoke_playlist.is_empty()
False
Sweeeet. Now we can belt some tunes. Which song is first?
>>> karaoke_playlist.peek()
'Try Everything -- Shakira'
Let's sing it!
>>> song = karaoke_playlist.dequeue()
Are we singing the right song?
>>> print(f"Now singing: {song}")
Now singing: Try Everything -- Shakira
Looks about right. What's next?
>>> karaoke_playlist.peek()
'Sing -- Pentatonix'
We can take a break now...
But let's see how our repr comes out, anyway.
>>> print(karaoke_playlist)
<Queue Front: Sing -- Pentatonix>
"""
def __init__(self):
"""Initialize queue."""
self.items = LinkedList()
def __repr__(self):
"""A human-readable representation of the queue instance."""
return f"<Queue Front: {self.peek()}>"
def is_empty(self):
"""Return True if no items in queue. Return False otherwise."""
return self.items.head is None
def enqueue(self, item):
"""Place an item at the back of the queue."""
self.items.append(item)
def dequeue(self):
"""Remove the item at the front of the queue and return it."""
front_item = self.items.head
self.items.remove(self.items.head.data)
return front_item.data
def peek(self):
"""Check the item at the front of the queue and return it."""
return self.items.head.data
def test_delete_with_item_not_in_list(self):
ll = LinkedList(['A', 'B', 'C'])
# Delete should raise error if item not found
with self.assertRaises(ValueError):
ll.delete('X') # Item not found in list
def __init__(self, init_size=8):
"""Create a new list (used as fixed-size array) of empty linked lists"""
"""Initialize this hash table with the given initial size."""
self.buckets = [LinkedList() for i in range(init_size)]
self.size = 0 # Number of key-value entries
def sort_linked_list(linked_list):
print("\n---------------------------")
print("The original linked list is:\n{0}".format(
linked_list.stringify_list()))
new_linked_list = LinkedList()
while linked_list.get_head_node():
max_val = find_max(linked_list)
new_linked_list.insert_beginning(max_val)
linked_list.remove_node(max_val)
return new_linked_list
#Test Cases for sort_linked_list
ll = LinkedList("Z")
ll.insert_beginning("C")
ll.insert_beginning("Q")
ll.insert_beginning("A")
print("The sorted linked list is:\n{0}".format(
sort_linked_list(ll).stringify_list()))
ll_2 = LinkedList(1)
ll_2.insert_beginning(4)
ll_2.insert_beginning(18)
ll_2.insert_beginning(2)
ll_2.insert_beginning(3)
ll_2.insert_beginning(7)
print("The sorted linked list is:\n{0}".format(
sort_linked_list(ll_2).stringify_list()))
def test_length_after_append_and_prepend(self):
ll = LinkedList()
assert ll.length() == 0
# Append and prepend should increase length
ll.append('C')
assert ll.length() == 1
ll.prepend('B')
assert ll.length() == 2
ll.append('D')
assert ll.length() == 3
ll.prepend('A')
assert ll.length() == 4
from linkedlist import Node, LinkedList
def deleteMiddleNode(input_list, del_node):
node = input_list.head
if not node or not node.next:
return
while (node.next != del_node):
node = node.next
node.next = del_node.next
# TESTS
my_list = LinkedList()
for elem in ['a', 'b', 'c', 'd', 'e', 'f']:
my_list.append(elem)
print("Before: ")
my_list.printList()
deleteMiddleNode(my_list, my_list.head.next.next)
print("After: ")
my_list.printList()
# This solution is O(n) time and O(1) space
def test_length_after_prepend(self):
ll = LinkedList()
assert ll.length() == 0
# Prepend should increase length
ll.prepend('C')
assert ll.length() == 1
ll.prepend('B')
assert ll.length() == 2
ll.prepend('A')
assert ll.length() == 3
def __init__(self, iterable=None):
self.list = LinkedList()
if iterable is not None:
for item in iterable:
self.enqueue_back(item)
def test_items_after_prepend(self):
ll = LinkedList()
assert ll.items() == []
# Prepend should add new item to head of list
ll.prepend('C')
assert ll.items() == ['C']
ll.prepend('B')
assert ll.items() == ['B', 'C']
ll.prepend('A')
assert ll.items() == ['A', 'B', 'C']
from linkedlist import LinkedList
from node import Node
import os
list = LinkedList()
node1 = Node('Bryan')
node2 = Node(18)
node3 = Node(True)
node4 = Node(3.40)
node1.next = node2
node2.next = node3
node3.next = node4
list.head = node1
list.tail = node4
def before_after(list):
os.system('clear')
print(" ----- BEFORE -----\n")
list.show()
print("\n Run...\n")
list.insert("Test", 1)
print("\n\n ----- AFTER -----\n")
list.show()
before_after(list)
def test_items_after_append(self):
ll = LinkedList()
assert ll.items() == []
# Append should add new item to tail of list
ll.append('A')
assert ll.items() == ['A']
ll.append('B')
assert ll.items() == ['A', 'B']
ll.append('C')
assert ll.items() == ['A', 'B', 'C']
class LinkedDeque(object):
def __init__(self, iterable=None):
self.list = LinkedList()
if iterable is not None:
for item in iterable:
self.enqueue_back(item)
def is_empty(self):
return self.list.size == 0
def front(self):
''' Returns the element in the front of the queueu
Worst Case Runtime - O(1) since the front of the queue is the head of the linkedlist
'''
if self.is_empty():
return None
return self.list.head.data
def length(self):
return self.list.size
def enqueue_front(self, item):
''' Adds an item in the front of the queue.
Worst Case Runtime : O(1) O(1) since we're just preppending
'''
self.list.prepend(item)
def enqueue_back(self, item):
''' Add an item in the back of the queue.
Worst Case Runtime : O(1) since we're just appending
'''
self.list.append(item)
def dequeue_front(self):
''' Pops and returns the element in the front of the queue.
Worst Case Runtime : O(1) since we just re-arrange the head's pointer
'''
if self.is_empty():
raise ValueError("Empty Queue")
item = self.list.head.data
if self.list.head == self.list.tail:
self.tail = self.head = None
else:
self.list.head = self.list.head.next
self.list.size -= 1
return item
def dequeue_back(self):
''' Pops and returns the element on the back of the queue.
Worst Case Runtime : O(n) since we must re-arrange the tail's pointer
'''
if self.is_empty():
raise ValueError("Empty queue")
if self.list.tail:
item = self.list.tail.data
curr = self.list.head
while curr is not None:
if curr.next == self.list.tail:
self.tail = curr
self.tail.next = None
curr = curr.next
self.list.size -= 1
return item
def test_init_with_list(self):
ll = LinkedList(['A', 'B', 'C'])
# Initializer should append items in order
assert ll.head.data == 'A' # First item
assert ll.tail.data == 'C' # Last item
def __init__(self, init_size=2000):
"""Initialize this hash table with the given initial size"""
self.buckets = [LinkedList() for i in range(init_size)]
def test_find_missing_in_list(self):
linked_list = LinkedList()
with self.assertRaises(LookupError):
linked_list.find("Smith")
# https://www.geeksforgeeks.org/write-a-c-function-to-print-the-middle-of-the-linked-list/
# Middle of linked list
import sys
sys.path.append('/home/sarthak/code/DataStructures/Linked_Lists')
from linkedlist import LinkedList
ll = LinkedList(12)
ll.add(27)
ll.add(29)
ll.add(39)
ll.add(49)
ll.add(59)
ll.add(69)
ll.add(40)
def middle(ll):
head = ll.head
mid = head
while head != None:
mid = mid.next
head = head.next.next
return mid
ll.printAll()
print("=============")
print middle(ll).data
def __init__(self):
"""Initialize queue."""
self.items = LinkedList()