Maximal Rectangle

Invariant: When cell (r,c) is processed, every predecessor state already meets its definition; the new state aggregates every legal way to enter the cell exactly as required.

candidate confidence: 0.607 · metadata_only

Invariant: Stack indexes increase, their values are monotone in the chosen direction, and every stored index has not yet encountered a right-side item that resolves it.

candidate confidence: 0.735 · metadata_only

Invariant: After each input prefix, frames from bottom to top are exactly the unfinished contexts in opening order, and the top is the only context directly affected next.

candidate confidence: 0.488 · metadata_only