class PriorityQueue(object):
'''
Priority Q based on Heaps. You can set min heap of max heap. Default is Max Heap.
1) Iterating yields (item, priority) tuples
'''
def __init__(self, reverse_priority = False):
'''
creates a priority queue such that priority 10 is processed first than priority 2. If you want
to reverse this set reverse_priority so that item with priority 2 is processed first
'''
self._heap = Heap(min_heap = reverse_priority)#create the heap as needed. Default Max heap
def add_item(self, item = None, priority = None):
if item == None:
return #we are not wasting time
self._heap.add_item(PriorityQueueEntry(item = item, priority = priority))
def get(self):
priority_q_entry = self._heap.get()
if priority_q_entry == None:
return None
return priority_q_entry.item
def __len__(self):
return self._heap.heap_size
def __iter__(self):
for priority_q_entry in self._heap:
yield (priority_q_entry.item, priority_q_entry.priority)
class MaxHeap_TestCase_1000_Pops_With_RandomSet_Of_1000_Elements(
unittest.TestCase):
"""
Create only. No heap modification. Small predictable set of elements.
"""
def setUp(self):
self._heap = Heap(min_heap=False)
def test_heap_status_on_push_pop(self):
self.assertFalse(self._heap.is_min_heap, 'heap must be a max heap.')
for i in range(1000):
self._heap.add_item(randint(0, 1000))
self.assertTrue(
assert_max_heap_property(self._heap._get_heap_as_list()),
'heap property must be satisfied.')
#pop all
for i in range(1000):
self._heap.get()
self.assertTrue(
assert_max_heap_property(self._heap._get_heap_as_list()),
'heap property must be satisfied.')
def tearDown(self):
unittest.TestCase.tearDown(self)
class MaxHeap_TestCase_Create_With_One_Element(unittest.TestCase):
"""
Create only. No heap modification. Only one element.
"""
def setUp(self):
self._heap = Heap(min_heap=False)
self._heap.add_item(3)
def test_heap_status(self):
self.assertFalse(self._heap.is_min_heap, 'heap must be a max heap.')
self.assertTrue(
assert_max_heap_property(self._heap._get_heap_as_list()),
'heap property must be satisfied.')
self.assertTrue([None, 3] == self._heap._get_heap_as_list(),
'heap contents are not same as expected.')
def tearDown(self):
unittest.TestCase.tearDown(self)
'''
Created on Oct 25, 2015
@author: hari
'''
from __future__ import print_function
from builtins import str
from pycoils.trees.heap import Heap
if __name__ == '__main__':
# A max heap. for a min heap use minHeap = True (is default)
max_heap = Heap(min_heap = False)
elements = [0, 4, 3, 2, 5, 1, 6]
print('Adding elements to heap: %s' % elements)
for element in elements:
max_heap.add_item(element)
print('Getting element from max heap')
element = max_heap.get()
print('Top element from heap is %s' % str(element))
print('Iterating through heap')
for element in max_heap:
print('heap popped %s' % str(element))
