- Remove middle element
"""
from singlyLL import SinglyLL
def delete_middle(head):
""" Delete middle element of a linked list """
fast_node = head
slow_node = head
prev_node = None
while fast_node and fast_node.next is not None:
prev_node = slow_node
slow_node = slow_node.next
fast_node = fast_node.next.next
print('Deleting middle element ' + str(slow_node.data))
prev_node.next = slow_node.next
if __name__ == '__main__':
ll = SinglyLL()
for i in range(0, 20):
ll.append(i)
print(ll.display())
delete_middle(ll.head)
print(ll.display())
def find_nth_from_last2(head, pos):
""" Find nth item from the end without length"""
ref_node = head
main_node = head
cur_pos = 1
while cur_pos is not pos:
ref_node = ref_node.next
cur_pos += 1
while ref_node.next is not None:
main_node = main_node.next
ref_node = ref_node.next
return main_node.data
if __name__ == '__main__':
sll = SinglyLL()
for i in range(0, 10):
sll.append(i)
print(sll.display())
print(find_nth_from_last2(sll.head, 2))
print(find_nth_from_last1(sll.head, 2, sll.size() - 1))
"""
For testing
"""
from singlyLL import SinglyLL
if __name__ == '__main__':
sll = SinglyLL()
for i in range(0, 10):
sll.append(i)
print(sll.display())
print(sll.size())
print(sll.get_node_at_index(12))
sll.print_node(sll.get_node_at_index(3))
if __name__ == '__main__':
# ll = SinglyLL()
# for i in range(1, 9):
# ll.append(i)
# print(ll.display())
# reverse_linked_list(ll)
# print(ll.display())
# ll2 = SinglyLL()
# for i in range(0, 6):
# ll2.append(i)
# print(ll2.display())
# ll2.head = reverse_linked_list_recursive(ll2.head)
# print(ll2.display())
print('Reverse every K Node')
ll3 = SinglyLL()
for i in range(18, 9, -1):
ll3.append(i)
print(ll3.display())
ll3.head = reverse_in_groups(ll3.head, 3)
print(ll3.display())
# print('Reverse every K node, alternatively')
# ll4 = SinglyLL()
# for i in range(3, 9):
# ll4.append(i)
# print(ll4.display())
# ll4.head = reverse_in_groups_alt(ll4.head, 2, True)
# print(ll4.display())
""" remove a loop """
main_node = head
while True:
ref_node = loop_node
while ref_node.next != loop_node and ref_node.next != main_node:
ref_node = ref_node.next
if ref_node.next == main_node:
break
main_node = main_node.next
ref_node.next = None
if __name__ == '__main__':
# Single Linked List
ll = SinglyLL()
for i in range(1, 5):
insert_node_at(ll.head, i, 0)
detect_loop(ll.head)
# Single Linked list with loop
lll = SinglyLL()
create_ll_with_loop(lll)
detect_loop(lll.head)
# after removal of loop
detect_loop(lll.head)
prev = l3.next
if l1 is not None:
l1 = l1.next
if l2 is not None:
l2 = l2.next
if carry < 0:
l3.append(carry)
print(l3.display())
if __name__ == '__main__':
l1 = SinglyLL()
l1.append(3)
l1.append(4)
l1.append(5)
print(l1.display())
l2 = SinglyLL()
l2.append(2)
l2.append(5)
l2.append(9)
l2.append(8)
print(l2.display())
l3 = SinglyLL()
add_two_numbers(l1.head, l2.head, l3.head)
prev_node = cur_node
cur_node = next_node
count += 1
if next_node:
if is_alt:
is_alt = False
else:
is_alt = True
head.next = reverse_in_groups_alt(next_node, k, is_alt)
return prev_node
if __name__ == '__main__':
ll = SinglyLL()
for i in range(1, 9):
ll.append(i)
print(ll.display())
reverse_linked_list(ll)
print(ll.display())
ll2 = SinglyLL()
for i in range(0, 6):
ll2.append(i)
print(ll2.display())
ll2.head = reverse_linked_list_recursive(ll2.head)
print(ll2.display())
print('Reverse every K Node')
ll3 = SinglyLL()
"""
from singlyLL import SinglyLL
def find_middle(head):
""" Find middle element in a linkedlist """
slow_node = head
fast_node = head
"""taking fast_node not none condition to
prevent nontype error in case of odd number
of nodes.
"""
while fast_node and fast_node.next is not None:
slow_node = slow_node.next
fast_node = fast_node.next.next
return slow_node.data
if __name__ == '__main__':
sll = SinglyLL()
for i in range(0, 10):
sll.append(i)
print(sll.display())
print(find_middle(sll.head))
def remove_dup_sorted_list(head):
""" remove duplicate elements from a sorted list """
cur_node = head
while cur_node.next is not None:
prev_node = cur_node
cur_node = cur_node.next
if cur_node.data == prev_node.data:
prev_node.next = cur_node.next
if __name__ == '__main__':
print('Removing Dups from an unsorted list')
sll = SinglyLL()
sll.append(2)
sll.append(3)
sll.append(4)
sll.append(2)
sll.append(5)
sll.append(3)
print(sll.display())
remove_dup(sll.head)
print(sll.display())
print('*' * 10)
new_node = Node(data)
cur_pos = 0
# invalid index
if position > sll.size():
print('Invalid index')
return False
# First node
if cur_node is None:
print('adding first node')
cur_node = Node(data)
return cur_node
while cur_node is not None:
if cur_pos == position:
print('adding new node at pos ' + str(cur_pos))
prev_node.next = new_node
new_node.next = cur_node
prev_node = cur_node
cur_node = cur_node.next
cur_pos += 1
if __name__ == '__main__':
sll = SinglyLL()
for index, value in enumerate(range(3, 9)):
insert_node_at(sll, value, 0)
print(sll.display())
print(sll.size())