def add_lists(lst1, lst2):
h1 = lst1.head
h2 = lst2.head
ans = LinkedList()
carry = 0
while h1 or h2:
if not h1:
result = h2.data + carry
h1 = h1.next
elif not h2:
result = h1.data + carry
h2 = h2.next
else:
result = h1.data + h2.data + carry
h1 = h1.next
h2 = h2.next
carry = 1 if result >= 10 else 0
ans.append_to_tail(result - carry * 10)
return ans
def delete_kth_last_node(ll: LinkedList, k: int) -> None:
# case for head node removal
if k == len(ll):
temp = ll.head
if len(ll) == 1:
ll.head = None
ll.rear = None
else:
ll.head = temp.next
temp.next = None
ll.length -= 1
del temp
return
# generic node removal
ptr_end = ll.head
ptr_k = ll.head
# moving the ptr_end up by k nodes
for _ in range(k + 1):
if ptr_end is None:
raise ValueError(f"Linked list contains less than {k} nodes")
ptr_end = ptr_end.next
# searching for the end of the linked list
# ptr_k is trailing the ptr_end up by k nodes, when end pointer reaches the end,
# ptr_k is k nodes away from the end
while ptr_end is not None:
ptr_end = ptr_end.next
ptr_k = ptr_k.next
# removing the required element
temp = ptr_k.next
ptr_k.next = temp.next
temp.next = None
ll.length -= 1
del temp
def test1(self):
lst = LinkedList(1, 2, 3, 3, 4)
required = LinkedList(1, 2, 3, 4)
remove_duplicate_nodes(lst)
self.assertEqual(lst, required)
def sort(ll: LinkedList) -> LinkedList:
ll.head = merge_sort(ll, ll.head)
# reseting rear
curr = ll.head
while curr.next:
curr = curr.next
ll.rear = curr
return ll
def test4(self):
lst1 = LinkedList(3, 1, 5)
lst2 = LinkedList(5, 9, 2)
required = LinkedList(8, 0, 8)
ans = add_lists(lst1, lst2)
self.assertEqual(ans, required)
def rotate_linked_list(ll: LinkedList, k: int = 0) -> None:
k = k % ll.length
for _ in range(k):
temp = ll.head
ll.head = ll.head.next
temp.next = None
ll.rear.next = temp
ll.rear = ll.rear.next
def test3(self):
lst = LinkedList(1, 1, 3, 1, 1)
n = lst.get_node(3)
remove_node_from_middle(n)
required = LinkedList(1, 1, 1, 1)
self.assertEqual(lst, required)
def reverse_inplace(ll: LinkedList) -> None:
ll.rear = ll.head
ptr_prev, ptr_curr, ptr_next = None, ll.head, ll.head.next
# reversing the flow
while ptr_curr is not None:
ptr_curr.next = ptr_prev
ptr_prev, ptr_curr = ptr_curr, ptr_next
if ptr_next is None:
break
ptr_next = ptr_next.next
ll.head = ptr_prev
def test5(self):
lst = LinkedList(1, 2, 3, 4, 5)
n = lst.get_node(3)
lst.get_node(5).next = n
self.assertEqual(is_circular(lst), True)
lst1 = LinkedList(1, 2, 3, 4)
self.assertEqual(is_circular(lst1), False)
def __init__(self, hashTableSize=defaultHashTableSize):
# Should probably be named HashTableEntry. You get the point.
self.buckets = [LinkedList() for x in range(0, hashTableSize)]
# A quick lookup for has() and getKeys().
self.keys = {}
def add_node_sorted(ll: LinkedList, val: int) -> None:
ll.length += 1
if not ll.head:
ll.head = Node(val)
ll.rear = ll.head
elif val > ll.rear.val:
ll.rear.next = Node(val)
ll.rear = ll.rear.next
else:
pos = ll.head
while pos.val < val:
pos = pos.next
temp = pos.val
pos.val = val
new_node = Node(temp)
new_node.next = pos.next
pos.next = new_node
if pos == ll.rear:
ll.rear = new_node
def add_linked_lists(ll1: LinkedList, ll2: LinkedList) -> LinkedList:
sum_linked_list = LinkedList()
pos1, pos2 = ll1.head, ll2.head
carry, curr_position_sum = 0, 0
# generating the sum of the linked lists
while pos1 or pos2:
if pos1 == None:
curr_position_sum = pos2.val + carry
if curr_position_sum >= 10:
carry, curr_position_sum = 1, curr_position_sum - 10
else:
carry = 0
elif pos2 == None:
curr_position_sum = pos1.val + carry
if curr_position_sum >= 10:
carry, curr_position_sum = 1, curr_position_sum - 10
else:
carry = 0
else:
curr_position_sum = pos2.val + pos1.val + carry
if curr_position_sum >= 10:
carry, curr_position_sum = 1, curr_position_sum - 10
else:
carry = 0
sum_linked_list.add(curr_position_sum)
# moving to the next value
if pos1:
pos1 = pos1.next
if pos2:
pos2 = pos2.next
if carry == 1:
sum_linked_list.add(1)
return sum_linked_list
def clone(ll: LinkedList) -> LinkedList:
clone_head = ll.head
pos1 = ll.head
pos2 = ll.head.next
# duplicating all elements (by value in the linked list)
# [a -> b -> c becomes a -> a -> b -> b -> c -> c]
for _ in range(ll.length):
pos1.next = Node(pos1.val)
pos1 = pos1.next
pos1.next = pos2
pos1 = pos1.next
if pos2 is None:
break
pos2 = pos2.next
# setting the clone head to the proper position
clone_head = clone_head.next
pos1 = ll.head
# setting the random pointer of the cloned linked list
# (every 2nd element in the new linked list: a -> [a] -> b -> [b] -> c -> [c])
for _ in range(ll.length - 1):
pos1.next.random_ptr = pos1.random_ptr
pos1 = pos1.next.next
# reverting the linked list to its original form
pos1 = ll.head
pos2 = ll.head.next
for _ in range(ll.length - 1):
pos1.next = pos2.next
pos2.next = pos2.next.next
pos1 = pos1.next
if pos2.next == None:
break
pos2 = pos2.next
# creating the cloned linked list from the generated nodes
cloned_LL = LinkedList()
cloned_LL.head = clone_head
cloned_LL.length = ll.length
cloned_LL.rear = pos2
return cloned_LL
def delete_zero_sum(linked_list: LinkedList) -> LinkedList:
cumulative = 0
cumulative_sum_map = {}
dummy_head = Node(0)
dummy_head.next = linked_list.head
linked_list.head = dummy_head
# removing 0 sum nodes using the property:
# x -> y -> x [values (x and y) are cumulative sums] implies the linked list
# contains x -> (y - x) -> -(y - x) and hence the nodes at the end can be removed
# [this property can also be used to detect multiple nodes summing up to 0]
node = linked_list.head
while node:
cumulative += node.val
if cumulative in cumulative_sum_map:
cumulative_sum_map[cumulative].next = node.next
cumulative_sum_map[cumulative] = node
node = node.next
# resetting the linked list (removing dummy head and setting rear)
linked_list.head = linked_list.head.next
node = linked_list.head
while node:
linked_list.rear = node
node = node.next
return linked_list
def merge_sorted_linked_list(list_of_LL: List[LinkedList]) -> LinkedList:
k = len(list_of_LL)
position_arr = [LL.head for LL in list_of_LL]
sorted_ll = LinkedList()
while any(position_arr):
# finding the node with minimum value
minimum = maxsize
for i in range(k):
if position_arr[i] is not None:
if position_arr[i].val < minimum:
minimum = position_arr[i].val
position = i
# generating new node
if sorted_ll.head is None:
sorted_ll.add(position_arr[position].val)
curr_position = sorted_ll.head
else:
curr_position.next = Node(position_arr[position].val)
curr_position = curr_position.next
sorted_ll.length += 1
position_arr[position] = position_arr[position].next
# resetting rear
sorted_ll.rear = curr_position
return sorted_ll
def testNewLinkedList(self):
self.new_list = LinkedList()
assert self.new_list.head == None
cumulative += node.val
if cumulative in cumulative_sum_map:
cumulative_sum_map[cumulative].next = node.next
cumulative_sum_map[cumulative] = node
node = node.next
# resetting the linked list (removing dummy head and setting rear)
linked_list.head = linked_list.head.next
node = linked_list.head
while node:
linked_list.rear = node
node = node.next
return linked_list
if __name__ == "__main__":
linked_list = LinkedList()
for elem in [3, 4, -7, 5, -6, 6]:
linked_list.add(elem)
print(delete_zero_sum(linked_list))
linked_list = LinkedList()
for elem in [7, 4, -4, -7, 5, -6, 6]:
linked_list.add(elem)
print(delete_zero_sum(linked_list))
linked_list = LinkedList()
for elem in [7, 4, -4, -7, 5, -6, 6, 10]:
linked_list.add(elem)
print(delete_zero_sum(linked_list))
"""
SPECS:
def swap_nodes(ll: LinkedList) -> Node:
node1 = ll.head
node2 = ll.head.next
while True:
try:
node1.val, node2.val = node2.val, node1.val
node1, node2 = node1.next.next, node2.next.next
except:
break
return ll.head
if __name__ == "__main__":
LL = LinkedList()
LL.add(1)
LL.add(2)
LL.add(3)
LL.add(4)
print(LL)
print(swap_nodes(LL))
"""
SPECS:
TIME COMPLEXITY: O(n)
SPACE COMPLEXITY: O(1)
"""
def rearrange(ll: LinkedList) -> None:
nodes_count = len(ll)
nodes = [int(node) for node in ll]
nodes.sort()
for i in range(2, nodes_count, 2):
nodes[i], nodes[i - 1] = nodes[i - 1], nodes[i]
curr = ll.head
for i in range(nodes_count):
curr.val = nodes[i]
curr = curr.next
if __name__ == "__main__":
LL = LinkedList()
for i in range(1, 6):
LL.add(i)
print(LL)
rearrange(LL)
print(LL)
"""
SPECS:
TIME COMPLEXITY: O(n)
SPACE COMPLEXITY: O(n)
"""
fast = fast.next.next
return slow
def sort(ll: LinkedList) -> LinkedList:
ll.head = merge_sort(ll, ll.head)
# reseting rear
curr = ll.head
while curr.next:
curr = curr.next
ll.rear = curr
return ll
if __name__ == "__main__":
LL = LinkedList()
for val in [6, 3, 7, 5, 30, 2, 50]:
LL.add(val)
print(LL)
sort(LL)
print(LL)
print()
LL = LinkedList()
for val in [4, 1, -3, 99]:
LL.add(val)
print(LL)
length = len(ll)
if length in (0, 1):
return ll
for _ in range(length):
pos1, pos2 = randint(0, length - 1), randint(0, length - 1)
node1, node2 = ll.head, ll.head
for _ in range(pos1):
node1 = node1.next
for _ in range(pos2):
node2 = node2.next
node1.val, node2.val = node2.val, node1.val
return ll
if __name__ == "__main__":
ll = LinkedList()
for i in range(1, 6):
ll.add(i)
print(ll)
shuffle(ll)
print(ll)
"""
SPECS:
TIME COMPLEXITY: O(n ^ 2)
SPACE COMPLEXITY: O(1)
"""
def setup_class(self):
print("Linked list tests")
self.makeLinkedList = lambda self, initial_data=None: LinkedList(
initial_data)
def __init__(self) -> None:
self.List = LinkedList()
self.start = None
self.end = None
def test2(self):
lst = LinkedList(1, 1, 3, 1, 1)
self.assertEqual(find_nth(lst, 3), 3)
def create_linked_list(val: int) -> LinkedList:
LL = LinkedList()
while val > 0:
LL.add(val % 10)
val = val // 10
return LL
# generating new node
if sorted_ll.head is None:
sorted_ll.add(position_arr[position].val)
curr_position = sorted_ll.head
else:
curr_position.next = Node(position_arr[position].val)
curr_position = curr_position.next
sorted_ll.length += 1
position_arr[position] = position_arr[position].next
# resetting rear
sorted_ll.rear = curr_position
return sorted_ll
if __name__ == "__main__":
LL1 = LinkedList()
LL1.add(2)
LL1.add(25)
LL1.add(70)
LL2 = LinkedList()
LL2.add(5)
LL2.add(8)
LL2.add(14)
LL2.add(15)
LL2.add(21)
LL2.add(48)
LL3 = LinkedList()
LL3.add(0)
LL3.add(90)
from DataStructures.LinkedList import LinkedList from DataStructures.Element import Element # Test cases # Set up some Elements e1 = Element(1) e2 = Element(2) e3 = Element(3) e4 = Element(4) # Start setting up a LinkedList ll = LinkedList(e1) ll.append(e2) ll.append(e3) # Test get_position # Should print 3 print(ll.head.next.next.value) # Should also print 3 print(ll.get_position(3).value) # Test insert ll.insert(e4, 3) # Should print 4 now print(ll.get_position(3).value) # Test delete ll.delete(1) # Should print 2 now print(ll.get_position(1).value)
class TestLinkedList:
new_list = LinkedList()
def testNewLinkedList(self):
self.new_list = LinkedList()
assert self.new_list.head == None
def testAddNode(self):
self.new_list.addNode('node_1')
assert self.new_list.head.data == 'node_1'
def testGetLength(self):
size = self.new_list.length()
assert size == 1
self.new_list.addNode('node_2')
size = self.new_list.length()
assert size == 2
self.new_list.addNode('node_3')
self.new_list.addNode('node_4')
def testStr(self):
print(self.new_list)
def testDelOldestNode(self):
node = self.new_list.delOldestNode()
assert self.new_list.length() == 3
assert node == 'node_1'
def testDelNewestNode(self):
node = self.new_list.delNewestNode()
assert self.new_list.length() == 2
assert node == 'node_4'
import sys
sys.path.append("../")
from DataStructures.LinkedList import LinkedList,Element
try:
print("Start LinkedList Tests ..")
# Set up some Elements
e1 = Element(1)
e2 = Element(2)
e3 = Element(3)
e4 = Element(4)
# Start setting up a LinkedList
ll = LinkedList(e1)
ll.append(e2)
ll.append(e3)
# Test cases
# Should print 3
assert ll.head.next.next.value == 3
# Test get_position
# Should print 3
assert ll.get_position(3).value == 3
# Test insert
ll.insert(e4,3)
# Should print 4 now
elif len1 > len2:
pos = len1 - len2
for _ in range(pos):
pos1 = pos1.next
# checking for intersecting node
for _ in range(smaller_len):
if pos1 is pos2:
return pos1
pos1 = pos1.next
pos2 = pos2.next
# no intersection
return None
if __name__ == "__main__":
ll1 = LinkedList()
ll1.add(5)
ll1.add(6)
ll1.add(7)
ll1.add(8)
ll2 = LinkedList()
ll2.add(1)
ll2.add(2)
ll2.add(3)
ll2.add(4)
ll3 = LinkedList()
ll3.add(9)
ll3.rear.next = ll1.head.next.next
ll3.rear = ll3.rear.next.next
def distribute(a_list, val):
c = LinkedList()
#print('distribute ', a_list, "| val ", val)
for elem in a_list:
c.append(val + elem.data)
return c