remember Mario's solution

Author: Robb Kidd

2022/ruby/day02-short.rb

@@ -0,0 +1,73 @@
+### Not My Solution ###
+#
+# much shorter and simpler because there are only
+# 9 combinations of possible outcomes for a round 
+class Day02
+  def self.go
+    day = new
+    puts "Part 1: #{day.part1}"
+    puts "Part 2: #{day.part2}"
+  end
+
+  def initialize(input=nil)
+    @input = input || real_input
+  end
+
+  # @example
+  #   day.part1 #=> 15
+  def part1
+    @input
+      .split("\n")
+      .map { |line|
+        PART1_MAP.fetch(line)
+      }
+      .reduce(&:+)
+  end
+
+  # map lifted wholesale from https://github.com/mfinelli/advent-of-code/blob/af64b2d7082b3616029b8ec680cbcc60e9219403/src/y22d02.rs
+  PART1_MAP = {
+    "A X" => 4, # rock v. rock (1) / draw (3)
+    "A Y" => 8, # rock v. paper (2) / win (6)
+    "A Z" => 3, # rock v. scissors (3) / lose (0)
+    "B X" => 1, # paper v. rock (1) / lose (0)
+    "B Y" => 5, # paper v. paper (2) / draw (3)
+    "B Z" => 9, # paper v. scissors (3) / win (6)
+    "C X" => 7, # scissors v. rock (1) / win (6)
+    "C Y" => 2, # scissors v. paper (2) / lose (0)
+    "C Z" => 6, # scissors v. scissors (3) / draw (3)
+  }
+
+  # @example
+  #   day.part2 #=> 12
+  def part2
+    @input
+      .split("\n")
+      .map { |line|
+        PART2_MAP.fetch(line)
+      }
+      .reduce(&:+)
+  end
+
+  # map lifted wholesale from https://github.com/mfinelli/advent-of-code/blob/af64b2d7082b3616029b8ec680cbcc60e9219403/src/y22d02.rs
+  PART2_MAP = {
+    "A X" => 3, # rock v. lose (scissors): 0 + 3 = 3
+    "A Y" => 4, # rock v. draw (rock): 3 + 1 = 4
+    "A Z" => 8, # rock v. win (paper): 6 + 2 = 8
+    "B X" => 1, # paper v. lose (rock): 0 + 1 = 1
+    "B Y" => 5, # paper v. draw (paper): 3 + 2 = 5
+    "B Z" => 9, # paper v. win (scissors): 6 + 3 = 9
+    "C X" => 2, # scissors v. lose (paper): 0 + 2 = 2
+    "C Y" => 6, # scissors v. draw (scissors): 3 + 3 = 6
+    "C Z" => 7, # scissors v. win (rock): 6 + 1 = 7
+  }
+
+  def real_input
+    File.read('../inputs/day02-input.txt')
+  end
+
+  EXAMPLE_INPUT = <<~INPUT
+    A Y
+    B X
+    C Z
+  INPUT
+end