class IHOP_LL(object):
def __init__(self, iterable=None):
self.list = LonkedList()
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 length(self): # O(1)
return self.list.length()
def is_empty(self): # O(1)
if self.length() > 0:
return False
return True
def push(self, item): # O(1)
self.list.prepend(item)
def peek(self): # O(1)
if self.is_empty():
return
return self.list.head.data
def pop(self): # O(1)
if self.is_empty():
raise ValueError
data = self.list.head.data
self.list.delete(self.list.head.data)
return data
def test_delete(self):
ll = LinkedList(['A', 'B', 'C'])
ll.delete('A')
assert ll.head.data == 'B' # new head
assert ll.tail.data == 'C' # unchanged
assert ll.size == 2
ll.delete('C')
assert ll.head.data == 'B' # unchanged
assert ll.tail.data == 'B' # new tail
assert ll.size == 1
ll.delete('B')
assert ll.head is None # new head
assert ll.tail is None # new head
assert ll.size == 0
with self.assertRaises(ValueError):
ll.delete('X') # item not in list
def test_replace(self):
ll = LinkedList(['A', 'B', 'C'])
ll.replace('A', 'D')
assert ll.head.data == 'D' # new head
assert ll.tail.data == 'C' # unchanged
assert ll.size == 3
ll.replace('B', 'E')
assert ll.head.data == 'D' # unchanged
assert ll.tail.data == 'C' # unchanged
assert ll.size == 3
ll.replace('C', 'F')
assert ll.head.data == 'D' # unchanged
assert ll.tail.data == 'F' # new tail
assert ll.size == 3
with self.assertRaises(ValueError):
ll.replace('X', 'Y') # item not in list
def test_get_at_index(self):
ll = LinkedList(['A', 'B', 'C'])
assert ll.get_at_index(0) == 'A' # head item
assert ll.get_at_index(1) == 'B' # middle item
assert ll.get_at_index(2) == 'C' # tail item
with self.assertRaises(ValueError):
ll.get_at_index(3) # index too high
with self.assertRaises(ValueError):
ll.get_at_index(-1) # index too low
def test_prepend(self):
ll = LinkedList()
# Prepend should always update head node
ll.prepend('C')
assert ll.head.data == 'C' # New head
assert ll.tail.data == 'C' # New head
ll.prepend('B')
assert ll.head.data == 'B' # New head
assert ll.tail.data == 'C' # Unchanged
ll.prepend('A')
assert ll.head.data == 'A' # New head
assert ll.tail.data == 'C' # Unchanged
class LinkedQ:
def __init__(self, iterable=None):
self.list = LonkedList()
if iterable:
for item in iterable:
self.enqueue(item)
def __repr__(self):
"""Return a string representation of this queue."""
return 'Queue({} items, front={})'.format(self.length(), self.front())
def __iter__(self):
for item in self.list:
yield item
def is_empty(self):
if self.length() > 0:
return False
return True
def length(self):
return self.list.length()
def front(self):
if self.length() > 0:
return self.list.head.data
return
def enqueue(self, item):
self.list.append(item)
def dequeue(self):
if self.is_empty():
raise ValueError
data = self.list.head.data
self.list.delete(self.list.head.data)
return data
def test_append(self):
ll = LinkedList()
# Append should always update tail node
ll.append('A')
assert ll.head.data == 'A' # New head
assert ll.tail.data == 'A' # New tail
ll.append('B')
assert ll.head.data == 'A' # Unchanged
assert ll.tail.data == 'B' # New tail
ll.append('C')
assert ll.head.data == 'A' # Unchanged
assert ll.tail.data == 'C' # New tail
def test_prepend(self):
ll = LinkedList()
ll.prepend('C')
assert ll.head.data == 'C' # new head
assert ll.tail.data == 'C' # new head
assert ll.size == 1
ll.prepend('B')
assert ll.head.data == 'B' # new head
assert ll.tail.data == 'C' # unchanged
assert ll.size == 2
ll.prepend('A')
assert ll.head.data == 'A' # new head
assert ll.tail.data == 'C' # unchanged
assert ll.size == 3
def test_prepend_append(self):
l = LinkedList()
l.prepend('Z')
assert l.head.data == 'Z'
assert l.tail.data == 'Z'
l.append('B')
assert l.head.data == 'Z'
assert l.tail.data == 'B'
l.prepend('A')
assert l.head.data == 'A'
assert l.tail.data == 'B'
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 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']
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']
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 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 __init__(self, iterable=None):
self.list = LonkedList()
if iterable is not None:
for item in iterable:
self.push(item)
def test_insert_at_index(self):
ll = LinkedList()
ll.insert_at_index(0, 'B') # append('B')
assert ll.head.data == 'B' # new head (at index 0)
assert ll.tail.data == 'B' # new tail (at index 0)
assert ll.size == 1
ll.insert_at_index(0, 'A') # prepend('A')
assert ll.head.data == 'A' # new head (at index 0)
assert ll.tail.data == 'B' # unchanged (now at index 1)
assert ll.size == 2
ll.insert_at_index(2, 'D') # append('D')
assert ll.head.data == 'A' # unchanged (at index 0)
assert ll.tail.data == 'D' # new tail (now at index 2)
assert ll.size == 3
ll.insert_at_index(2, 'C') # insert 'C' between 'B' and 'D'
assert ll.head.data == 'A' # unchanged (at index 0)
assert ll.tail.data == 'D' # unchanged (now at index 3)
assert ll.size == 4
with self.assertRaises(ValueError):
ll.insert_at_index(5, 'X') # index too high
with self.assertRaises(ValueError):
ll.insert_at_index(-1, 'Y') # index too low
def test_size(self):
ll = LinkedList()
assert ll.size == 0
# append and prepend operations increment size
ll.append('B')
assert ll.size == 1
ll.prepend('A')
assert ll.size == 2
ll.append('C')
assert ll.size == 3
# delete operations decrement size
ll.delete('B')
assert ll.size == 2
ll.delete('C')
assert ll.size == 1
ll.delete('A')
assert ll.size == 0
def test_length(self):
ll = LinkedList()
assert ll.length() == 0
# append and prepend operations increase length
ll.append('B')
assert ll.length() == 1
ll.prepend('A')
assert ll.length() == 2
ll.append('C')
assert ll.length() == 3
# delete operations decrease length
ll.delete('B')
assert ll.length() == 2
ll.delete('C')
assert ll.length() == 1
ll.delete('A')
assert ll.length() == 0
def test_items(self):
ll = LinkedList()
assert ll.items() == []
ll.append('B')
assert ll.items() == ['B']
ll.prepend('A')
assert ll.items() == ['A', 'B']
ll.append('C')
assert ll.items() == ['A', 'B', 'C']
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
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_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 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 __init__(self, iterable=None):
self.list = LonkedList()
if iterable:
for item in iterable:
self.enqueue(item)
def test_find(self):
ll = LinkedList(['A', 'B', 'C'])
assert ll.find(lambda item: item == 'B') == 'B'
assert ll.find(lambda item: item < 'B') == 'A'
assert ll.find(lambda item: item > 'B') == 'C'
assert ll.find(lambda item: item == 'X') is None