heap-mapping

This is a library containing an implementation of the min-max heap data structure, which allows for $O(1)$ retrieval and $O(log(n))$ removal of both the minimum and maximum elements of the heap, as well as $O(log(n))$ insertion of keys and changes to their priorities. Heap creation can be additionally performed in $O(n)$ time.

The data structure can be accessed as MutableMapping; keys are the "values" stored in the data structure, and values are their priorities.

Getting started

You can construct a MinMaxHeap from a list of values.

from heap_mapping import MinMaxHeap

heap = MinMaxHeap([5, 0, 4, 1, 2, 9, 8])
print(heap.min_value) # 0
print(heap.max_value) # 9

By default, priorities are the same as the values.

print(heap[5]) # 5

You can specify a key function in the constructor to get a priority from each element.

heap2 = MinMaxHeap([5, 0, 4, 1, 2, 9, 8], key=lambda x: -x)
print(heap2.min_value) # 9
print(heap2.max_value) # 0
print(heap2[5]) # -5

You can add elements with the add method. By default, the key function specified in the constructor is used to get the priority.

heap2.add(7)
print(heap2[7]) # -7

Alternatively, you can manually specify a key.

heap2.add(6, -3)
print(heap2[6]) # -3

You can change the priorities after they've been inserted.

heap2[7] = 1
print(heap2.max_value) # 7

You can look up and delete arbitrary elements in $O(log(n))$ time.

del heap2[6]
print(6 in heap2) # False

Iteration is performed out of order. Note that this order is also not the order in which the elements are stored in the heap!

print(list(heap2)) # [5, 0, 4, 1, 2, 9, 8, 7]