From 2d6f1dfec79f7a1f41385597b675cc5d7a1cf525 Mon Sep 17 00:00:00 2001
From: Allan Taylor <allan.taylor.pi@gmail.com>
Date: Sun, 24 Dec 2023 20:21:02 +1300
Subject: [PATCH] 2023 Day 24

---
 2023/24.py | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 inputs     |  2 +-
 2 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 2023/24.py

diff --git a/2023/24.py b/2023/24.py
new file mode 100644
index 0000000..98b2500
--- /dev/null
+++ b/2023/24.py
@@ -0,0 +1,74 @@
+import os
+from pathlib import Path
+from time import perf_counter
+import z3
+import numpy.linalg as la
+timer_script_start=perf_counter()
+SCRIPT_PATH=Path(os.path.realpath(__file__))
+INPUT_PATH=SCRIPT_PATH.parent.parent/"inputs"/Path(SCRIPT_PATH.parent.name,SCRIPT_PATH.stem+".txt")
+timer_parse_start=perf_counter()
+############################## PARSER ##############################
+XY_LB = 200000000000000
+XY_UB = 400000000000000
+def is_in_test_area(point):
+    return point is not None and all(XY_LB<=c<=XY_UB for c in point)
+class Point2D:
+    def __init__(self,x,y,dx,dy):
+        self.x = x
+        self.y = y
+        self.dx = dx
+        self.dy = dy
+    def intersect(self,other:"Point2D"):
+        try:
+            t1, t2 = la.solve([[self.dx,-other.dx],[self.dy,-other.dy]],[other.x-self.x,other.y-self.y])
+        except la.LinAlgError:
+            print(f"Failed to intersect {self} and {other}")
+        else:
+            if t1<0 or t2<0:
+                return None # in the past
+            return (self.x+t1*self.dx,self.y+t1*self.dy)
+        return None # Parallel lines
+    
+    def __repr__(self) -> str:
+        return f"Point2D({self.x}, {self.y}, {self.dx}, {self.dy})"
+
+class Point3D:
+    def __init__(self,x,y,z,dx,dy,dz):
+        self.x = x
+        self.y = y
+        self.z = z
+        self.dx = dx
+        self.dy = dy
+        self.dz = dz
+    
+    def __repr__(self) -> str:
+        return f"Point3D({self.x}, {self.y}, {self.z}, {self.dx}, {self.dy}, {self.dz})"
+
+with open(INPUT_PATH) as file:
+    lines = file.read().splitlines()
+point_tuples = [tuple(map(int,line.replace(" @",",").split(', '))) for line in lines]
+points2d = [Point2D(x,y,dx,dy) for x,y,z,dx,dy,dz in point_tuples]
+points3d = [Point3D(x,y,z,dx,dy,dz) for x,y,z,dx,dy,dz in point_tuples]
+timer_parse_end=timer_part1_start=perf_counter()
+############################## PART 1 ##############################
+p1 = sum(is_in_test_area(a.intersect(b)) for i,a in enumerate(points2d) for b in points2d[i+1:])
+print("Part 1:",p1)
+timer_part1_end=timer_part2_start=perf_counter()
+############################## PART 2 ##############################
+x,y,z,u,v,w = map(z3.Int,"xyzuvw")
+ts = [z3.Int(f"t{i}") for i in range(len(point_tuples))]
+s = z3.Solver()
+for t,c in zip(ts,points3d):
+    s.add(x+t*u == c.x+t*c.dx)
+    s.add(y+t*v == c.y+t*c.dy)
+    s.add(z+t*w == c.z+t*c.dz)
+s.check()
+m = s.model()
+p2 = sum(m[c].as_long() for c in (x,y,z))
+print("Part 2:",p2)
+timer_part2_end=timer_script_end=perf_counter()
+print(f"""Execution times (sec)
+Parse: {timer_parse_end-timer_parse_start:3.3f}
+Part1: {timer_part1_end-timer_part1_start:3.3f}
+Part2: {timer_part2_end-timer_part2_start:3.3f}
+Total: {timer_script_end-timer_script_start:3.3f}""")
diff --git a/inputs b/inputs
index 8dad0ba..2b21a90 160000
--- a/inputs
+++ b/inputs
@@ -1 +1 @@
-Subproject commit 8dad0bac43e370260d585f6c7bc6b727c7f3828d
+Subproject commit 2b21a906b1535f612b51e1d47283a7a84a4dc99f