built-in max heap API in Python

Question

Default heapq is min queue implementation and wondering if there is an option for max queue? Thanks.

I tried the solution using _heapify_max for max heap, but how to han

Answer 1

In the past I have simply used sortedcontainers's SortedList for this, as:

> a = SortedList()
> a.add(3)
> a.add(2)
> a.add(1)
> a.pop()
3

It's not a heap, but it's fast and works directly as required.

If you absolutely need it to be a heap, you could make a general negation class to hold your items.

class Neg():
    def __init__(self, x):
        self.x = x

    def __cmp__(self, other):
        return -cmp(self.x, other.x)

def maxheappush(heap, item):
    heapq.heappush(heap, Neg(item))

def maxheappop(heap):
    return heapq.heappop(heap).x

But that will be using a little more memory.