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."""
# 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()
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
return self.heap.delete_min()
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
min_item = self.heap.items[0]
self.heap.items[0] = (priority, item)
if self.heap._last_index != 0:
self.heap._bubble_down(0)
return min_item
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 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]
class PriorityQueue:
def __init__(self):
self._heap = BinaryMinHeap()
self._max_priority = 0
self._min_priority = 0
def _update_minmax(self, priority):
if priority > self._max_priority:
self._max_priority = priority
if priority < self._min_priority:
self._min_priority = priority
@property
def size(self):
return self._heap.size
@property
def front(self):
if self.is_empty() is False:
return self._heap.get_min().value
else:
return None
def dequeue(self):
return self._heap.delete_min().value
def enqueue(self, item):
self.insert_back(item)
def push_pop(self, item):
self.insert_back(item)
return self._heap.delete_min().value
def is_empty(self):
return self._heap.is_empty()
def insert(self, item, priority):
self._heap.insert(KVHolder(priority, item))
self._update_minmax(priority)
def insert_front(self, item):
priority = self._min_priority - 1
self.insert(item, priority)
def insert_back(self, item):
priority = self._max_priority + 1
self.insert(item, priority)
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_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]
def test_is_empty_on_non_empty_heap(self):
heap = BinaryMinHeap()
heap.insert(1)
assert heap.is_empty() == False
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]
if __name__ == "__main__":
runtime = []
results = []
print "####################################################"
print("Test Case 1")
bheap = BinaryMinHeap()
results.append(compare_var(bheap.is_empty(), True, "=="))
results.append(compare_var(bheap.peek_min(), None, "=="))
results.append(compare_var(bheap.remove_min(), None, "=="))
results.append(compare_var(bheap.peek_array(), [], "=="))
print "####################################################"
print("Test Case 2")
val = 5
print("\nAdd one value to the heap: {0}".format(val))
bheap.insert(val)
results.append(compare_var(bheap.is_empty(), False, "=="))
results.append(compare_var(bheap.peek_min(), val, "=="))
results.append(compare_var(bheap.peek_array(), [5], "=="))
print "####################################################"
print("Test Case 3")
print("\nRemove min value to the heap: {0}".format(val))
results.append(compare_var(bheap.remove_min(), val, "=="))
results.append(compare_var(bheap.is_empty(), True, "=="))
results.append(compare_var(bheap.peek_min(), None, "=="))
results.append(compare_var(bheap.peek_array(), [], "=="))
print "####################################################"
print("Test Case 4")
print("\nInsert multiple values into binary heap")
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]
