--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/day7.rb	Thu Dec 07 21:06:48 2023 +0000
@@ -0,0 +1,37 @@
+#! /usr/bin/env ruby
+
+require 'set'
+
+if ARGV.length != 1
+        abort("Incorrect arguments - needs input file")
+elsif not File.exist? (ARGV[0])
+	abort("File #{ARGV[0]} did not exist")
+end
+
+file = ARGV[0]
+
+Hand = Struct.new(:cards, :score, :bid)
+
+$card_scoring = ("1".."9").to_a.concat(["T", "J", "Q", "K", "A"])
+
+FULL_HOUSE = Set.new([2,3])
+TWO_PAIR = {2 => 2, 1 => 1}
+
+def score_hand(cards)
+	card_vals = cards.each_char.map {|c| $card_scoring.index(c)}
+	card_counts = card_vals.group_by{|v| v}.map {|k, v| v.length}
+	card_count_counts = card_counts.group_by{|v| v}.map{|k,v| [k, v.length]}.to_h
+	of_a_kind = card_counts.max
+	rank = of_a_kind * 2 # 5, 4 or 3 of a kind or a pair => 10, 8, 6 and 4
+	if Set.new(card_counts) == FULL_HOUSE
+		rank = 7	
+	elsif card_count_counts == TWO_PAIR
+		rank = 5
+	end
+	card_vals.reduce("#{rank-1}") {|str, v| "#{str}.#{(v+1).to_s.rjust(2, '0')}"}
+end
+
+hands = File.open(file, "r").each_line(chomp: true).map {|line| cards, bid = line.split(" "); Hand.new(cards, score_hand(cards), bid.to_i)}
+
+puts hands.sort {|a, b| a.score <=> b.score}.map.with_index(1) {|val, i| i * val.bid}.sum
+# Rest of algorithm here
\ No newline at end of file