LeetCode Card 318 — 1D Dynamic Programming / Structure
Pattern signal
This pattern usually appears when the prompt involves best value or count depends on a previous line of states. Climbing Stairs, House Robber, Decode Ways, and coin-change style questions often land here.
What Structure means here
In BASIC, the Structure step is where you state the invariant, helper contract, or control-flow skeleton before coding. For 1D Dynamic Programming, 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
The miss is starting recurrence discussion before the state meaning is nailed down. 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 1D Dynamic Programming, what is the simplest way to state the invariant, helper contract, or control-flow skeleton before coding?”