Tier 2 · Archmagematch

Run Of Five

A hand is five cards as "2H 3S 4D 5C 6H" — rank then suit, space separated, and always sorted by rank, ascending. The rank ladder is A 2 3 4 5 6 7 8 9 T J Q K: the ace is low, so A-2-3-4-5 is a run and A-T-J-Q-K is not. Match a hand whose five ranks are consecutive on that ladder.

Regex cannot add one to a rank, so "consecutive" has to be spelled out — but you only ever need to spell out the twelve adjacent *pairs*, not the nine whole runs. Because the hand is sorted, a run is nothing more than four adjacent pairs in a row, and a lookahead lets you check a pair without consuming the card you are standing on.

cards lookahead alternation

Your pattern0 chars · par 74

Flags

Start typing — tests run as you go.

Test cases

2H 3S 4D 5C 6Hmust match
AS 2H 3D 4C 5Smust match
the wheel
9H TD JS QC KHmust match
2H 3S 4D 5C 7Hmust not match
a gap at the top
2H 2S 3D 4C 5Hmust not match
a pair, not a run
AS TH JD QC KSmust not match
the ace is low here, so this is not a run

+ 13 hidden tests, checked when you submit. They are what stops a pattern that only fits the examples above.