Onsite Coding: 2D DP (optimized to 1D) + Union-Find / Graph Search

Onsite coding included: A seemingly complex but straightforward 2D DP problem, later optimizable to 1D DP (prompt not provided). A problem solvable with Union-Find, and also via BFS/DFS (connectivity / grouping) (prompt not provided). Only the categories are known; the full prompts are not available.