Day 1: Report Repair

Functions:

find_pair_with_sum(items, total)

Find the two entries that sum to total.

find_pair_with_sum(items: List[int], total: int) → Optional[Tuple[int, int]]

Find the two entries that sum to total.

Ensures

• result is None
  or result[0] != result[1]
  or items.count(result[0]) > 1
  

  (A duplicated result was produced from different input items)

• result is not None ⇒ all(r in items for r in result)

  (Returned values appear in the input)

• result is not None ⇒ result[0] + result[1] == total

  (Returned items sum to the right total)