Got it. Here’s a tight, high-yield prep pack for your GEICO Coding Round 1 (Codility, Wed Sep 10, 2025, 9:00–9:45 AM ET).

Game plan (45 min):

• 0–2 min: Read both problems; pick the one you can solve in O(n) first.
• 2–25 min: Implement #1 with a clean API, handle edge cases, and add quick tests.
• 25–43 min: Implement #2 (or optimize #1 if only one).
• 43–45 min: Final pass—rename vars, add comments, re-run samples.

Edge-case checklist:

• Empty input
• Single element
• All same values
• Negatives/zeros
• Duplicates
• Ties
• Off-by-one on indices
• Large n (O(n) vs O(n log n))
• Overflow (use long if sums)
• Unicode/whitespace for strings if relevant.