Heap / Priority Queue Cheat Sheet

What is Heap / Priority Queue?

Maintain priority with heap-based data structures.

Template Code

import heapq

class KthLargest:
    def __init__(self, k: int, nums: List[int]):
        self.k = k
        self.heap = nums
        heapq.heapify(self.heap)
        
        while len(self.heap) > k:
            heapq.heappop(self.heap)
    
    def add(self, val: int) -> int:
        heapq.heappush(self.heap, val)
        
        if len(self.heap) > self.k:
            heapq.heappop(self.heap)
        
        return self.heap[0]

Complexity

Common Variations

• Basic Heap / Priority Queue
• Heap / Priority Queue with constraints
• Optimized Heap / Priority Queue

Practice Problems