day 14 puzzle 1

src/day14/puzzle1.typ

@@ -0,0 +1,61 @@
+#import "/src/utils.typ": *
+
+#let regexp = regex("^p=(.*?),(.*?) v=(.*?),(.*?)$")
+
+#let simulate(v0, dv, max: 1, steps: 1) = {
+  return calc.rem-euclid(v0 + dv * steps, max)
+}
+
+#let solve(w: 0, h: 0, steps: 100, input) = {
+  assert(w != 0, message: "Width must be != 0")
+  assert(h != 0, message: "Height must be != 0")
+
+  let bots = input.split("\n").map(b => {
+    let m = b.match(regexp)
+    return (
+      pos: (
+        x: int(m.captures.at(0)),
+        y: int(m.captures.at(1)),
+      ),
+      vel: (
+        x: int(m.captures.at(2)),
+        y: int(m.captures.at(3))
+      )
+    )
+  })
+
+  let quadrants = (
+    tl: 0,
+    tr: 0,
+    bl: 0,
+    br: 0
+  )
+  let half-w = calc.div-euclid(w, 2)
+  let half-h = calc.div-euclid(h, 2)
+
+  let sim-x = simulate.with(max: w, steps: steps)
+  let sim-y = simulate.with(max: h, steps: steps)
+  for bot in bots {
+    let x2 = sim-x(bot.pos.x, bot.vel.x)
+    let y2 = sim-y(bot.pos.y, bot.vel.y)
+
+    if x2 == half-w or y2 == half-h {
+      continue
+    }
+    let quadrant = (
+      (if y2 < half-h {"t"} else {"b"}) +
+      (if x2 < half-w {"l"} else {"r"})
+    )
+    quadrants.at(quadrant) += 1
+  }
+
+  return quadrants.values().product()
+}
+
+#show-puzzle(
+  14, 1,
+  solve.with(w: 101, h: 103),
+  example: (
+    (result: 12, args: (w: 11, h: 7)),
+  )
+)