LeetCode Card 329 — Monotonic Stack / Implement
Pattern signal
This pattern usually appears when the prompt involves next greater/smaller relationships or range influence determined by nearest boundary violations. Daily Temperatures, Next Greater Element, Trapping Rain Water variants, and histogram area problems are common.
What Implement means here
In BASIC, the Implement step is where you write the code in the same order as the chosen skeleton so the logic stays stable. For Monotonic Stack, 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 transcribe the plan instead of improvising. 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
The miss is pushing values instead of the right representation, or not naming the ordering maintained by the stack. 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 Monotonic Stack, what is the simplest way to write the code in the same order as the chosen skeleton so the logic stays stable?”