LeetCode Card 273 — Heaps and Priority Queues / Structure
Pattern signal
This pattern usually appears when the prompt involves repeated access to current min/max or top-k items under ongoing updates. Kth Largest Element, Top K Frequent, Merge K Sorted Lists, and scheduling problems frequently use heaps.
What Structure means here
In BASIC, the Structure step is where you state the invariant, helper contract, or control-flow skeleton before coding. For Heaps and Priority Queues, that matters because the pattern only becomes useful once the candidate is explicit about what is being tracked, reduced, or preserved.
Interview move
A strong move is to make the plan visible before full execution. In this pattern family, say out loud what representation makes the problem easier: the map entry, the pointer invariant, the recursion contract, the queue contents, or the DP state. That keeps the implementation attached to a reason.
Common miss
Candidates pick a heap without first defining what priority each entry should encode. BASIC reduces that risk because the stage sequence forces you to earn the implementation instead of jumping straight into it.
BASIC prompt
“Given that this looks like Heaps and Priority Queues, what is the simplest way to state the invariant, helper contract, or control-flow skeleton before coding?”