Created
April 10, 2015 14:08
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implementing a priority queue
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# example.py | |
# | |
# Example of a priority queue | |
import heapq | |
class PriorityQueue: | |
def __init__(self): | |
self._queue = [] | |
self._index = 0 | |
def push(self, item, priority): | |
heapq.heappush(self._queue, (-priority, self._index, item)) | |
self._index += 1 | |
def pop(self): | |
return heapq.heappop(self._queue)[-1] | |
# Example use | |
class Item: | |
def __init__(self, name): | |
self.name = name | |
def __repr__(self): | |
return 'Item({!r})'.format(self.name) | |
q = PriorityQueue() | |
q.push(Item('foo'), 1) | |
q.push(Item('bar'), 5) | |
q.push(Item('spam'), 4) | |
q.push(Item('grok'), 1) | |
print("Should be bar:", q.pop()) | |
print("Should be spam:", q.pop()) | |
print("Should be foo:", q.pop()) | |
print("Should be grok:", q.pop()) |
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