Module day02

Red-Nosed Reports

Computes boths parts simultaneously. Each pair of levels is converted into deltas of either +1, -1 or 0. For example:

• 1 3 6 7 9 => +1 +1 +1 +1
• 9 7 6 2 1 => -1 -1 0 -1

If the sum of all delta equals ±4, then we know that all levels are increasing or decreasing. Any other value indicates either mixed up and down transitions or levels that are too far apart.

For part two we remove each pair of deltas (or single delta at each end) then replace with the sum of the delta from the new neighbors on either side.

Functions

• check 🔒
• delta 🔒
  Convert each pair of levels to either +1 for increase, -1 for decrease or 0 for invalid range.
• parse
  Minimize allocation to only a single vec reused for each report.
• part1
• part2

Type Aliases

• Input 🔒