2024 day 13

2024/day13/day13.bqn

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+⟨lf,Split⟩←•Import"../bqn-libs/strings.bqn"
+in←>•ParseFloat¨¨¨2⊸↓¨¨¨", "⊸Split¨¨1⊸⊑¨¨": "⊸Split¨¨lf⊸Split¨(lf∾lf)Split ¯1↓•FChars"input"
+
+Solve←{offset𝕊⟨xa‿ya,xb‿yb,xp‿yp⟩:
+  xp‿yp+↩offset
+  na‿nb←{
+    # A and B are collinear, we should find the optimal solution,
+    # but I didn't need it for my input
+    𝕊0: 0‿0;
+    # General case
+    nb←((xp×ya)-yp×xa)÷𝕩
+    na←(xp-nb×xb)÷xa
+    # Check that solution is integer
+    {∧´⌊⊸=𝕩 ? 𝕩 ; 0‿0}na‿nb
+  }(xb×ya)-yb×xa
+}
+
+•Show +´+˝3‿1⊸ע0⊸Solve˘in
+•Show +´+˝3‿1⊸ע10000000000000⊸Solve˘in
+

2024/day13/test

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+Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400
+
+Button A: X+26, Y+66
+Button B: X+67, Y+21
+Prize: X=12748, Y=12176
+
+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450
+
+Button A: X+69, Y+23
+Button B: X+27, Y+71
+Prize: X=18641, Y=10279