day 3 puzzle 2

progress.yaml

@@ -3,4 +3,4 @@
 2:
   stars: 2
 3:
-  stars: 1
+  stars: 2

res/examples/day3_2.txt

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

src/day3/puzzle1.typ

@@ -12,5 +12,5 @@
 #show-puzzle(
   3, 1,
   solve,
-  example: 161
+  example: ("1": 161)
 )

src/day3/puzzle2.typ

@@ -0,0 +1,31 @@
+#import "/src/utils.typ": *
+
+#let solve(input) = {
+  let dos = input.matches(regex("do\(\)"))
+  let donts = input.matches(regex("don't\(\)"))
+  let toggles = dos.map(m => (m.end, true))
+  toggles += donts.map(m => (m.end, false))
+  toggles = toggles.sorted(key: t => t.first())
+
+  let is-enabled(i) = {
+    let t = toggles.rev().find(t => t.first() <= i)
+    return t == none or t.last()
+  }
+
+  let matches = input.matches(regex("mul\((\d{1,3}),(\d{1,3})\)"))
+  let total = matches.map(m => {
+    if is-enabled(m.start) {
+      m.captures.map(int)
+                .product()
+    } else {
+      0
+    }
+  }).sum()
+  return total
+}
+
+#show-puzzle(
+  3, 2,
+  solve,
+  example: ("2": 48)
+)

src/utils.typ

@@ -67,7 +67,14 @@
   )
 }
 
-#let show-puzzle(day, puzzle, func, example: none, visualize: none) = {
+#let show-puzzle(
+  day,
+  puzzle,
+  func,
+  example: none,
+  visualize: none,
+  only-example: false
+) = {
   let check-example = check-example.with(visualize: visualize)
   if example != none {
     if type(example) == dictionary {
@@ -80,10 +87,12 @@
     linebreak()
   }
 
+  if not only-example {
     let input = get-input(day)
     let result = (func)(input)
     show-result(result)
   }
+}
 
 #let day-template(day, puzzle1, puzzle2, stars: 0) = {
   pagebreak(weak: true)