Year 2016 Day 2

2016/day02.rb

@@ -0,0 +1,46 @@
+lines = STDIN.read.split("\n")
+
+DIFFS = {
+  'U' => [-1, 0],
+  'R' => [0, 1],
+  'D' => [1, 0],
+  'L' => [0, -1]
+}
+KEYPAD1 = [
+  [1, 2, 3],
+  [4, 5, 6],
+  [7, 8, 9]
+]
+pos = [1, 1]
+puts (
+  lines.map do |line|
+    line.chars.each do |instr|
+      new_pos = pos.zip(DIFFS[instr]).map(&:sum)
+      next unless [0, 1, 2].include?(new_pos.first)
+      next unless [0, 1, 2].include?(new_pos.last)
+      pos = new_pos
+    end
+    KEYPAD1[pos.first][pos.last]
+  end.join
+)
+
+KEYPAD2 = [
+  '..1..',
+  '.234.',
+  '56789',
+  '.ABC.',
+  '..D..'
+]
+pos = [2, 0]
+puts (
+  lines.map do |line|
+    line.chars.each do |instr|
+      new_pos = pos.zip(DIFFS[instr]).map(&:sum)
+      next if new_pos.first < 0 || new_pos.first >= KEYPAD2.size
+      next if new_pos.last < 0 || new_pos.last >= KEYPAD2.size
+      next if KEYPAD2[new_pos.first][new_pos.last] == '.'
+      pos = new_pos
+    end
+    KEYPAD2[pos.first][pos.last]
+  end.join
+)

2016/examples/day02.txt

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+ULL
+RRDDD
+LURDL
+UUUUD