Solve 2023 day 24 part 2 with Python Z3

Author: sim642

src/main/resources/eu/sim642/adventofcode2023/day24.py

@@ -0,0 +1,38 @@
+from z3 import *
+
+s = Solver()
+
+x, y, z = Reals("x y z")
+vx, vy, vz = Reals("vx vy vz")
+
+t0, t1, t2 = Reals("t0 t1 t2")
+
+# s.add(19 + t0 * -2 == x + t0 * vx)
+# s.add(13 + t0 * 1 == y + t0 * vy)
+# s.add(30 + t0 * -2 == z + t0 * vz)
+#
+# s.add(18 + t1 * -1 == x + t1 * vx)
+# s.add(19 + t1 * -1 == y + t1 * vy)
+# s.add(22 + t1 * -2 == z + t1 * vz)
+#
+# s.add(20 + t2 * -2 == x + t2 * vx)
+# s.add(25 + t2 * -2 == y + t2 * vy)
+# s.add(34 + t2 * -4 == z + t2 * vz)
+
+s.add(262130794315133 + t0 * 57 == x + t0 * vx)
+s.add(305267994111063 + t0 * -252 == y + t0 * vy)
+s.add(163273807102793 + t0 * 150 == z + t0 * vz)
+
+s.add(290550702673836 + t1 * -74 == x + t1 * vx)
+s.add(186986670515285 + t1 * 19 == y + t1 * vy)
+s.add(231769402282435 + t1 * -219 == z + t1 * vz)
+
+s.add(275698513286341 + t2 * -59 == x + t2 * vx)
+s.add(162656001312879 + t2 * -24 == y + t2 * vy)
+s.add(183065006152383 + t2 * -225 == z + t2 * vz)
+
+print(s.check())
+
+m = s.model()
+print(m)
+

src/main/scala/eu/sim642/adventofcode2023/Day24.scala

@@ -57,6 +57,14 @@ object Day24 {
     inters.size
   }
 
+  // throw: 6 unk
+  // per-hailstone: 3 eqs, 1 unk
+
+  // 0, 6
+  // 3, 7
+  // 6, 8
+  // 9, 9
+
 
   def parseHailstone(s: String): Hailstone = s match {
     case s"$x, $y, $z @ $vx, $vy, $vz" =>
@@ -71,5 +79,7 @@ object Day24 {
 
   def main(args: Array[String]): Unit = {
     println(countIntersections1(parseHailstones(input)))
+
+    // part 2: 554668916217145
   }
 }