Solve 2024 day 13

2024/d13.py

@@ -0,0 +1,33 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__)
+ps = data.split("\n\n")
+
+c1, c2 = 0, 0
+for p in ps:
+    lines = p.splitlines()
+    ax, ay = ints(lines[0])
+    bx, by = ints(lines[1])
+    px, py = ints(lines[2])
+    px2 = px + 10000000000000
+    py2 = py + 10000000000000
+
+    for a in range(0, 101):
+        for b in range(0, 101):
+            if a * ax + b * bx == px and a * ay + b * by == py:
+                c1 += a * 3 + b
+
+    D = ax * by - bx * ay
+    if abs(D) > 1e-10:
+        a_ = px2 * by - bx * py2
+        b_ = ax * py2 - px2 * ay
+        if a_ % D == 0 and b_ % D == 0:
+            a = (px2 * by - bx * py2) // D
+            b = (ax * py2 - px2 * ay) // D
+
+            if a >= 0 and b >= 0:
+                c2 += a * 3 + b
+
+print(c1)
+print(c2)

README.md

@@ -303,5 +303,6 @@ and focus. Of course, learning more algorithms and techniques helps.
 - Day 10: `00:19:47  2976      0   00:20:47  2244      0`
 - Day 11: `00:05:13   642      0   00:33:07  2673      0`
 - Day 12: `00:30:30  3540      0   11:41:33  16212     0`
-- Day 13:
+- Day 13: `00:05:35   225      0   00:55:48   2544      0`
+- Day 14: