Priority queue with higher priority first in Python

You can extend the Priority Queue to keep the logic unchanged:

from Queue import PriorityQueue

class DualPriorityQueue(PriorityQueue):
    def __init__(self, maxPQ=False):
        PriorityQueue.__init__(self)
        self.reverse = -1 if maxPQ else 1

    def put(self, priority, data):
        PriorityQueue.put(self, (self.reverse * priority, data))

    def get(self, *args, **kwargs):
        priority, data = PriorityQueue.get(self, *args, **kwargs)
        return self.reverse * priority, data


minQ = DualPriorityQueue()
maxQ = DualPriorityQueue(maxPQ=True)

minQ.put(10, 'A')
minQ.put(100, 'A')


maxQ.put(10, 'A')
maxQ.put(100,'A')

print "Min DQ: {}".format(minQ.get())
print "Max DQ: {}".format(maxQ.get())

Output:

Min DQ: (10, 'A')
Max DQ: (100, 'A')

Use a negative priority instead, no need to subtract from sys.maxint.

queue.put((-priority, item))

An item with priority -10 will be returned before items with priority -5, for example.