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priority_queue.py
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priority_queue.py
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"""
Implementation of priority queue using linear array.
Insertion - O(n)
Extract min/max Node - O(1)
"""
import collections
class PriorityQueueNode:
def __init__(self, data, priority):
self.data = data
self.priority = priority
def __repr__(self):
return str(self.data) + ": " + str(self.priority)
class PriorityQueue:
def __init__(self):
self.priority_queue_list = collections.deque()
def __repr__(self):
return "PriorityQueue({!r})".format(list(self.priority_queue_list))
def size(self):
return len(self.priority_queue_list)
def push(self, item, priority=None):
priority = item if priority is None else priority
node = PriorityQueueNode(item, priority)
for index, current in enumerate(self.priority_queue_list):
if current.priority > node.priority:
self.priority_queue_list.insert(index, node)
return
# when traversed complete queue
self.priority_queue_list.append(node)
def pop(self):
# remove and return the first node from the queue
return self.priority_queue_list.popleft()