day 25 puzzle 1

progress.yaml

@@ -45,4 +45,6 @@
 23:
   stars: 2
 24:
+  stars: 1
+25:
   stars: 1

res/examples/day25.txt

@@ -0,0 +1,39 @@
+#####
+.####
+.####
+.####
+.#.#.
+.#...
+.....
+
+#####
+##.##
+.#.##
+...##
+...#.
+...#.
+.....
+
+.....
+#....
+#....
+#...#
+#.#.#
+#.###
+#####
+
+.....
+.....
+#.#..
+###..
+###.#
+###.#
+#####
+
+.....
+.....
+.....
+#....
+#.#..
+#.#.#
+#####

src/day25/puzzle1.typ

@@ -0,0 +1,61 @@
+#import "/src/utils.typ": *
+
+#let parse-schematic(schematic) = {
+  let lines = schematic.split("\n")
+  let is-key = "." in schematic.first()
+
+  let n-cols = lines.first().len()
+  let n-rows = lines.len()
+  let heights = ()
+
+  for x in range(n-cols) {
+    let y = if is-key {n-rows - 2} else {1}
+    let h = 0
+    for i in range(n-rows) {
+      if lines.at(y).at(x) == "." {
+        break
+      }
+      h += 1
+      y += if is-key {-1} else {1}
+    }
+    heights.push(h)
+  }
+
+  return (if is-key {"key"} else {"lock"}, heights)
+}
+
+#let fits(lock, key) = {
+  let tmp = lock.zip(key).map(p => p.sum())
+  return calc.max(..tmp) <= 5
+}
+
+#let solve(input) = {
+  let schematics = input.split("\n\n")
+
+  let locks = ()
+  let keys = ()
+  for schematic in schematics {
+    let (type, heights) = parse-schematic(schematic)
+    if type == "key" {
+      keys.push(heights)
+    } else {
+      locks.push(heights)
+    }
+  }
+  let total = 0
+  for key in keys {
+    for lock in locks {
+      if fits(lock, key) {
+        total += 1
+      }
+    }
+  }
+
+  return total
+}
+
+#show-puzzle(
+  25, 1,
+  solve,
+  example: 3
+)