Day 3 solutions

Author: creideiki

03-1.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+
+from functools import reduce
+import re
+
+input = open('03.input').read()
+
+inst = re.compile('mul\\([0-9]+,[0-9]+\\)')
+
+print(reduce(lambda x, y: x + y,
+             map(lambda terms: int(terms[0]) * int(terms[1]),
+                 [mul[4:-1].split(',') for mul in re.findall(inst, input)])))

03-1.rb

@@ -0,0 +1,7 @@
+#!/usr/bin/env ruby
+
+input = File.read('03.input')
+
+inst = /mul\([[:digit:]]+,[[:digit:]]+\)/
+
+puts input.scan(inst).map { |mul| mul[4..-2].split(',').map(&:to_i).reduce(&:*) }.sum

03-2.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python
+
+from functools import reduce
+import re
+
+input = open('03.input').read()
+
+inst = re.compile('do\\(\\)|don\'t\\(\\)|mul\\([0-9]+,[0-9]+\\)')
+
+res = 0
+enabled = True
+
+for i in re.findall(inst, input):
+    match i:
+        case 'do()':
+            enabled = True
+        case 'don\'t()':
+            enabled = False
+        case _:
+            if enabled:
+                res += reduce(lambda x, y: x * y,
+                              map(lambda s: int(s),
+                                  i[4:-1].split(',')))
+
+print(res)

03-2.rb

@@ -0,0 +1,21 @@
+#!/usr/bin/env ruby
+
+input = File.read('03.input')
+
+inst = /do\(\)|don't\(\)|mul\([[:digit:]]+,[[:digit:]]+\)/
+
+res = 0
+enabled = true
+
+input.scan(inst).each do |i|
+  case i
+  when 'do()'
+    enabled = true
+  when 'don\'t()'
+    enabled = false
+  else
+    res += i[4..-2].split(',').map(&:to_i).reduce(&:*) if enabled
+  end
+end
+
+puts res

03.sample-2

@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))