Module day14

Disk Defragmentation

This problem is a blend of the hashing from Day 10 and the connected clique finding from Day 12 and reuses the same flood fill approach to count groups.

Structs

• Exclusive 🔒
  Regular data structures need to be protected by a mutex.
• Shared
  Atomics can be safely shared between threads.

Functions

• dfs 🔒
  Flood fill that explores the connected squares in the grid.
• fill_row 🔒
  Compute the knot hash for a row and expand into an array of bytes.
• knot_hash 🔒
  Slightly tweaked version of the code from Day 10 that always performs 64 rounds.
• parse
  Parallelize the hashing as each row is independent.
• part1
• part2
• worker 🔒
  Each worker thread chooses the next available index then computes the hash and patches the final vec with the result.