class PriorityQueue(object):
"""PriorityQueue: a partially ordered queue with methods to enqueue items
in priority order and to access and dequeue its highest priority item.
Item pairs are stored in a binary min heap for its efficient operations."""
def __init__(self):
"""Initialize this priority queue."""
# Initialize new binary min heap to store items in this priority queue
self.heap = BinaryMinHeap()
def __repr__(self):
"""Return a string representation of this priority queue."""
return 'PriorityQueue({} items, front={})'.format(self.size, self.front())
def size(self):
"""returns the number of items in the queue"""
return self.heap.size()
def is_empty(self):
"""Return True if this priority queue is empty, or False otherwise."""
return self.heap.is_empty()
def length(self):
"""Return the number of items in this priority queue."""
return self.heap.size()
def enqueue(self, item, priority=0):
"""Insert the given item into this priority queue in order according to
the given priority."""
# Insert given item into heap in order according to given priority
self.heap.insert((priority, item))
def front(self):
"""Return the item at the front of this priority queue without removing
it, or None if this priority queue is empty."""
if self.size() == 0:
return None
# Return minimum item from heap
return self.heap.get_min()[1]
def dequeue(self):
"""Remove and return the item at the front of this priority queue,
or raise ValueError if this priority queue is empty."""
if self.size() == 0:
raise ValueError('Priority queue is empty and has no front item')
# Remove and return minimum item from heap
return self.heap.delete_min()[1]
def push_pop(self, item, priority):
"""Remove and return the item at the front of this priority queue,
and insert the given item in order according to the given priority.
This method is more efficient than calling dequeue and then enqueue."""
if self.size() == 0:
raise ValueError('Priority queue is empty and has no front item')
# Replace and return minimum item from heap
self.heap.items[0], popped_item = (priority, item), self.heap.items[0]
self.heap._bubble_down(0)
return popped_item[1]
def test_insert_and_delete_many_random_items(self):
heap = BinaryMinHeap()
items = random.sample(range(1000), 50)
for item in items:
heap.insert(item)
assert heap.size() == len(items)
for item in sorted(items):
assert heap.delete_min() == item
assert heap.size() == 0
def test_insert_and_delete_many_items(self):
heap = BinaryMinHeap()
items = [9, 25, 86, 3, 29, 5, 55]
for item in items:
heap.insert(item)
assert heap.size() == len(items)
for item in sorted(items):
assert heap.delete_min() == item
assert heap.size() == 0
def test_insert_and_get_many_random_items(self):
heap = BinaryMinHeap()
items = random.sample(range(1000), 50)
for index, item in enumerate(items):
heap.insert(item)
assert heap.size() == index + 1
min_item = min(items[:index + 1])
assert heap.get_min() == min_item
assert heap.size() == len(items)
def test_insert_and_get_many_items(self):
heap = BinaryMinHeap()
items = [9, 25, 86, 3, 29, 5, 55]
for index, item in enumerate(items):
heap.insert(item)
assert heap.size() == index + 1
min_item = min(items[:index + 1])
assert heap.get_min() == min_item
assert heap.size() == len(items)
assert heap.items == [3, 9, 5, 25, 29, 86, 55]
def test_insert_and_get_one_item(self):
heap = BinaryMinHeap()
assert heap.is_empty() is True
heap.insert(5)
assert heap.is_empty() is False
assert heap.size() == 1
assert heap.get_min() == 5
assert heap.items == [5]
def heap_sort(items):
heap = BinaryMinHeap(items)
sorted_items = []
while heap.size() > 0:
sorted_items.append(heap.delete_min())
items[:] = sorted_items
class PriorityQueue(object):
""" PriorityQueue: a partially ordered queue with methods to enqueue items
in priority order and to access and dequeue its highest priority item.\n
Item pairs are stored in a binary min heap for its efficient operations. """
def __init__(self):
""" Initializes priority queue. """
self.heap = BinaryMinHeap(
) # Initializes new binary min heap to store items in priority queue
def __repr__(self):
""" Returns string representation of priority queue. """
return "PriorityQueue({} items, front={})".format(
self.size(), self.front())
def is_empty(self):
""" Returns True if priority queue is empty, else returns False. """
return self.heap.is_empty()
def length(self):
""" Returns number of items in priority queue. """
return self.heap.size()
def enqueue(self, item, priority):
""" Inserts given item into priority queue in order according to given priority. """
# TODO: Inserts given item into heap in order according to given priority
def front(self):
""" Returns item at front of priority queue without removing
it, or None if priority queue is empty. """
if self.size() == 0:
return None
# TODO: Returns minimum item from heap
# ...
def dequeue(self):
""" Removes and returns item at front of priority queue,
or raises ValueError if priority queue is empty. """
if self.size() == 0:
raise ValueError("Priority queue is empty and has no front item.")
# TODO: Removes and returns minimum item from heap
# ...
def push_pop(self, item, priority):
""" Removes and returns item at front of priority queue,
and inserts given item in order according to given priority.\n
This method is more efficient than calling dequeue and then enqueue."""
if self.size() == 0:
raise ValueError("Priority queue is empty and has no front item.")
def get_suggestion(org_handle, handle_array, k=2) -> [str]:
assert len(handle_array) >= k
suggestion_min_heap = BinaryMinHeap()
handle_set = set(org_handle) # O(c)
for handle in handle_array: # O(n)
if suggestion_min_heap.size() < k:
curr_score = get_score(handle_set, handle) # O(c)
suggestion_min_heap.insert((handle, curr_score)) # O(k)
elif suggestion_min_heap.get_min()[1] > len(
handle): # Check whether to get the score or not
continue
else:
curr_score = get_score(handle_set, handle) # O(c)
if curr_score > suggestion_min_heap.get_min()[1]:
suggestion_min_heap.replace_min((handle, curr_score))
return [x[0] for x in suggestion_min_heap.items] # O(k)
def test_size_of_empty_heap(self):
heap = BinaryMinHeap()
assert heap.size() == 0
def test_insert_and_delete_one_item(self):
heap = BinaryMinHeap()
heap.insert(5)
assert heap.size() == 1
assert heap.delete_min() == 5
assert heap.size() == 0
def test_insert_and_get_one_item(self):
heap = BinaryMinHeap()
heap.insert(5)
assert heap.size() == 1
assert heap.get_min() == 5
assert heap.items == [5]
class PriorityQueue(object):
"""
PriorityQueue: a partially ordered queue with methods to enqueue items
in priority order and to access and dequeue its highest priority item.
Item pairs are stored in a binary min heap for its efficient operations.
"""
def __init__(self):
"""Initialize this priority queue."""
# Initialize new binary min heap to store items in this priority queue
self.heap = BinaryMinHeap()
def __repr__(self):
"""Return a string representation of this priority queue."""
return 'PriorityQueue({} items, front={})'.format(
self.length(), self.front())
# def __str__(self):
# pass
def is_empty(self):
"""Return True if this priority queue is empty, or False otherwise."""
return self.heap.is_empty()
def length(self):
"""Return the number of items in this priority queue."""
return self.heap.size()
def enqueue(self, item, priority):
"""
Insert the given item into this priority queue in order according to
the given priority.
"""
# Insert given item into heap in order according to given priority
new_item = (item, priority)
self.heap.insert(new_item)
def front(self):
"""
Return the item at the front of this priority queue without removing
it, or None if this priority queue is empty.
"""
if self.length() == 0:
return None
return self.heap.get_min()[0]
def dequeue(self):
"""
Remove and return the item at the front of this priority queue,
or raise ValueError if this priority queue is empty.
"""
if self.length() == 0:
raise ValueError('Priority queue is empty and has no front item')
# delete the min element
front_elem = self.heap.delete_min()
return front_elem[0]
def push_pop(self, item, priority):
"""
Remove and return the item at the front of this priority queue,
and insert the given item in order according to the given priority.
This method is more efficient than calling dequeue and then enqueue.
"""
if self.length() == 0:
raise ValueError('Priority queue is empty and has no front item')
# store the old front item
old_front = self.front()
# replace the item at the 0th element with new item and its priority
self.heap.items[0] = (item, priority)
# print(f"new front item: {self.front()}")
return old_front[0]
class PriorityQueue(object):
"""PriorityQueue: a partially ordered queue with methods to enqueue items
in priority order and to access and dequeue its highest priority item.
Item pairs are stored in a binary min heap for its efficient operations."""
def __init__(self):
"""Initialize this priority queue."""
# Initialize new binary min heap to store items in this priority queue
self.heap = BinaryMinHeap()
def __repr__(self):
"""Return a string representation of this priority queue."""
return 'PriorityQueue({} items, front={})'.format(self.size(), self.front())
def is_empty(self):
"""Return True if this priority queue is empty, or False otherwise."""
return self.heap.is_empty()
def length(self):
"""Return the number of items in this priority queue."""
return self.heap.size()
def enqueue(self, item, priority):
"""Insert the given item into this priority queue in order according to
the given priority."""
# TODO: Insert given item into heap in order according to given priority
# ...
# Note that I probably could have done this with a list instead
self.heap.insert((priority, item))
def front(self):
"""Return the item at the front of this priority queue without removing
it, or None if this priority queue is empty."""
if self.size() == 0: # Basically, if the queue is empty, then just retirn that theres no front
return None
# TODO: Return minimum item from heap
# ...
front_item = self.heap.get_min()
return front_item[1]
def dequeue(self):
"""Remove and return the item at the front of this priority queue,
or raise ValueError if this priority queue is empty."""
if self.size() == 0:
raise ValueError('Priority queue is empty and has no front item')
# TODO: Remove and return minimum item from heap
# ...
last_item = self.heap.delete_min()
return last_item[1]
def push_pop(self, item, priority):
"""Remove and return the item at the front of this priority queue,
and insert the given item in order according to the given priority.
This method is more efficient than calling dequeue and then enqueue."""
if self.size() == 0:
raise ValueError('Priority queue is empty and has no front item')
# TODO: Replace and return minimum item from heap
# ...
popped_item = self.heap.replace_min(priority, item)
return popped_item[1]
