Heap

A Python binary heap supporting both min-heap and max-heap behavior. Each node (PQNode) must be unique and hashable. The heap allows fast insert, update, remove, and pop operations.

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Features

• Min-heap or max-heap (kind="min" or "max")
• Nodes store a key (used for ordering) and value (actual data)
• Duplicate nodes trigger a warning but are allowed
• O(log n) insert, update, pop, and remove

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Installation

Copy the Heap class and PQNode protocol into your project. No external dependencies required.

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Usage

from heap import Heap, PQNode
import warnings

class Node:
    def __init__(self, key, value):
        self.key = key       # Heap ordering
        self.value = value   # Unique data

    # Ensure uniqueness and hashability via `value`
    def __hash__(self):
        return hash(self.value)

    def __eq__(self, other):
        return isinstance(other, Node) and self.value == other.value

# Create a min-heap
heap = Heap(kind="min")

# Insert nodes
n1 = Node(5, "apple")
n2 = Node(2, "banana")
n3 = Node(8, "cherry")

heap.insert(n1)
heap.insert(n2)
heap.insert(n3)

# Pop the top element (smallest key)
top = heap.pop()
print(top.value, top.key)  # Output: banana 2

# Update a node's key
heap.update(n3, 1)
print(heap.pop().value, heap.pop().key)  # Output: cherry 1

# Remove a node
heap.remove(n1)