from tester import _assert_equal
from linkedlist import linkedlist_from_list
# delete_middle_node deletes a node, given that the node has
# both a parent, and a child.
def delete_middle_node(node):
# Your code here
pass
tests = [
[[1, 2, 3, 4, 5], 2, [1, 2, 4, 5]],
[[1, 3, 5], 1, [1, 5]],
[[1, 2, 3, 4, 5], 3, [1, 2, 3, 5]],
]
for test in tests:
first_ll = linkedlist_from_list(test[0])
pointer = first_ll
for i in range(0, test[1]):
pointer = pointer.n
delete_middle_node(pointer)
_assert_equal(linkedlist_from_list(test[2]), first_ll)
from linkedlist import linkedlist_from_list
from tester import runtests
# The partition function should take a linked list and a value.
# the linked list should be modified inplace such that all values
# less than the value end up in the first half of the list, and the
# values greater than or equal to the passed value end up in the
# second half of the list.
def partition(ll, val):
# Your code here
pass
tests = [
[[linkedlist_from_list([1, 2, 3, 3, 4, 5]), 3], linkedlist_from_list([1, 2, 3, 3, 4, 5])],
[[linkedlist_from_list([3, 3, 4, 5, 1, 2]), 3], linkedlist_from_list([1, 2, 3, 3, 4, 5])],
[[linkedlist_from_list([6, 2, 33, 3, 44, 5]), 6], linkedlist_from_list([2, 3, 5, 6, 33, 44])],
[[linkedlist_from_list([]), 3], linkedlist_from_list([])],
[[linkedlist_from_list([6]), 3], linkedlist_from_list([6])],
[[linkedlist_from_list([3, 2]), 3], linkedlist_from_list([2, 3])]
]
runtests(tests, partition, inplace=True)
from linkedlist import linkedlist_from_list
from tester import runtests
# is_loop should return True if there is a loop in the linked list.
# That is, if any node in the linked list points to a node earlier in the list (or itself).
def is_loop(ll):
# Your code here
pass
test1 = linkedlist_from_list([1])
test1.n = test1
test2 = linkedlist_from_list([1, 2, 3, 4, 5])
test2.n.n.n.n = test2
test3 = linkedlist_from_list([1, 2, 3, 4])
test3.n.n.n = test3
test4 = linkedlist_from_list([1, 2, 3, 4])
test4.n.n.n = test4.n.n
tests = [
[[test1], True],
[[test2], True],
[[test3], True],
[[test4], True],
[[linkedlist_from_list([1, 2, 3, 3, 4, 5])], False],
[[linkedlist_from_list([1])], False],
[[linkedlist_from_list([])], False],
]
from linkedlist import linkedlist_from_list
from tester import runtests
# kth_from_last should return the k-th-from-last element in the linked list ll.
def kth_from_last(k, ll):
# Your code here
pass
tests = [
[[5, linkedlist_from_list([1, 2, 3, 3, 4, 5])], 1],
[[0, linkedlist_from_list([5, 4, 3, 2, 5 ,1])], 1],
[[1, linkedlist_from_list([1, 1])], 1],
[[0, linkedlist_from_list([1])], 1],
[[2, linkedlist_from_list(['always', 'always', 'remove', 'duplicates'])], 'always'],
[[1, linkedlist_from_list([1, 2, 3, 1, 3, 0])], 3]
]
runtests(tests, kth_from_last)
from linkedlist import linkedlist_from_list
from tester import runtests
# remove_dups should modify ll inplace to remove any nodes of the linked list
# with duplicate values.
def remove_dups(ll):
# Your code here
pass
tests = [
[[linkedlist_from_list([1, 2, 3, 3, 4, 5])], linkedlist_from_list([1, 2, 3, 4, 5])],
[[linkedlist_from_list([5, 4, 3, 2, 5 ,1])], linkedlist_from_list([5, 4, 3, 2, 1])],
[[linkedlist_from_list([1, 1])], linkedlist_from_list([1])],
[[linkedlist_from_list([1])], linkedlist_from_list([1])],
[[linkedlist_from_list(['always', 'always', 'remove', 'duplicates'])], linkedlist_from_list(['always', 'remove', 'duplicates'])],
[[linkedlist_from_list([])], linkedlist_from_list([])],
[[linkedlist_from_list([1, 2, 3, 1, 3, 0])], linkedlist_from_list([1, 2, 3, 0])]
]
runtests(tests, remove_dups, inplace=True)
from linkedlist import linkedlist_from_list
from tester import runtests
# palindromically_reorder should modify the passed linked list inplace such that
# the i'th node of the list will be followed by the N-1-i'th node.
# Sounds confusing. Is a little. Have a look at the test cases.
def palindromically_reorder(ll):
# Your code here
pass
tests = [
[[linkedlist_from_list([1, 2, 3, 4, 5])], linkedlist_from_list([1, 5, 2, 4, 3])],
[[linkedlist_from_list([1, 2, 3, 3, 4, 5])], linkedlist_from_list([1, 5, 2, 4, 3, 3])],
[[linkedlist_from_list([])], linkedlist_from_list([])],
[[linkedlist_from_list([1])], linkedlist_from_list([1])],
[[linkedlist_from_list([1, 2])], linkedlist_from_list([1, 2])],
[[linkedlist_from_list([1, 2, 3])], linkedlist_from_list([1, 3, 2])],
]
runtests(tests, palindromically_reorder, inplace=True)
from linkedlist import linkedlist_from_list
from tester import runtests
# palindrome should return True if ll represents a palindrome.
def palindrome(ll):
# Your code here
pass
tests = [
[[linkedlist_from_list([1, 2, 3, 2, 1])], True],
[[linkedlist_from_list([1, 2, 3, 3, 2, 1])], True],
[[linkedlist_from_list([1, 2, 3, 4, 2, 1])], False],
[[linkedlist_from_list([1, 2, 3, 3, 2, 2])], False],
[[linkedlist_from_list([1, 2])], False],
[[linkedlist_from_list([1])], True],
[[linkedlist_from_list([])], True],
]
runtests(tests, palindrome)
from linkedlist import linkedlist_from_list
from tester import runtests
# sum_lists should take two linked lists, treat them as if they were decimal numbers,
# and return a list that represents the sum of those numbers. (see tests for examples)
def sum_lists(l1, l2):
# Your code here
pass
tests = [
[[linkedlist_from_list([1, 2, 3, 3, 4]), linkedlist_from_list([1, 2, 3, 3, 4])], linkedlist_from_list([2, 4, 6, 6, 8])],
[[linkedlist_from_list([1, 5, 0]), linkedlist_from_list([1, 5, 0])], linkedlist_from_list([3, 0, 0])],
[[linkedlist_from_list([9, 9]), linkedlist_from_list([1])], linkedlist_from_list([1, 0, 0])],
[[linkedlist_from_list([9]), linkedlist_from_list([9])], linkedlist_from_list([1, 8])],
[[linkedlist_from_list([]), linkedlist_from_list([])], linkedlist_from_list([])],
[[linkedlist_from_list([9, 9, 9, 9, 9]), linkedlist_from_list([2])], linkedlist_from_list([1, 0, 0, 0, 0, 1])],
[[linkedlist_from_list([1, 0, 0, 0, 0]), linkedlist_from_list([2])], linkedlist_from_list([1, 0, 0, 0, 0, 2])],
]
runtests(tests, sum_lists)
