What is Heap / Priority Queue

heap (priority queue with $O(\log n)$ operations) maintains elements with efficient access to the minimum or maximum, supporting insert and extract in $O(\log n)$. You use it when repeatedly finding the smallest or largest element from a changing collection. Heaps enable $O(n \log n)$ sorting and $O(n \log k)$ selection of top k elements.

You'll see this in scheduling, merging, and streaming data problems. If you can explain these concepts in your own words, you'll solve related problems faster under interview pressure.