day-7

2023 Day 7: Camel Cards

• Solution from orlp [Rust]

Benchmarks (with parsing, no I/O)

CPU	Part 1	Part 2
i5-1240P@1.7-4.4GHz	21.549 µs	21.490 µs
i5-12600K@3.7-4.9GHz	18.899 µs	18.772 µs

Explanation

Counting pairs, triples, etc.

• is_joker: Indicates which positions are jokers. 1 nibble (4 bits) per position, so 5
• counts: Indicates how many times each card appears. 1 nibble per card label
• count_occurences: Indicates how many times each count occurs, i.e. how many cards occur 0,1,2,3,4,5 times. Sum of nibbles is 13 (number of different labels)

cards:                      KTJJT
is_joker:                 0x00110

                    AKQJT98765432
counts:           0x0102200000000

                           543210
count occurences: 0x000000000021a

cards:                      QQQJA
is_joker:                 0x00010

                    AKQJT98765432
counts:           0x1031000000000

                           543210
count occurences: 0x000000000102a

Determine if hand is FiveOfAKind, FourOfAKind, etc.

count_occurences can only be one of these values:

  543210
0x10000c -> FiveOfAKind
0x01001b -> FourOfAKind
0x00110b -> FullHouse
0x00102a -> ThreeOfAKind
0x00021a -> TwoPairs
0x000139 -> OnePair
0x000058 -> FiveUnique