LeetCode Card 324 — 2D Dynamic Programming / Implement
Pattern signal
This pattern usually appears when the prompt involves state depends on two indices, two strings, or grid-like subproblems. Longest Common Subsequence, Edit Distance, unique paths with obstacles, and many grid optimizations fit here.
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 2D 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 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
Candidates drown in table details because they never define what each cell actually means. 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 2D Dynamic Programming, what is the simplest way to write the code in the same order as the chosen skeleton so the logic stays stable?”