Checkpoint: two bugs, one method

secondMax teaches the deepest lesson of the module: the original else branch silently records the LAST smaller value, not the second LARGEST — a semantic error invisible to a single test. And the -1 report via max == second breaks for negatives (try {-1, -2}: max stays 0!). The repair needs a proper two-slot tracker and a boolean 'was there a second?' — exactly the kind of redesign the exam asks you to diagnose, not just the one-token fixes.