Year 2024, Day 13

Author: Schlauer-Hax

clients/typescript/solutions/S2413.ts

@@ -0,0 +1,57 @@
+import ISolution from "./ISolution.ts";
+import * as mathjs from "npm:mathjs";
+
+export default class S2413 implements ISolution {
+    firstPart(input: string): (number | string) | Promise<number | string> {
+        const prizes = input.split("\n\n")
+            .map(prize => prize.split("\n").map(l => l.split(": ")[ 1 ].split(", ")))
+            .map(([ a, b, prize ]) => ({ a: a.map(o => Number(o.slice(1))), b: b.map(o => Number(o.slice(1))), prize: prize.map(p => Number(p.slice(2))) }));
+        let sum = 0;
+        for (const prize of prizes) {
+            const options = [];
+            for (let ia = 0; ia < 100; ia++) {
+                for (let ib = 0; ib < 100; ib++) {
+                    const x = ia * prize.a[ 0 ] + ib * prize.b[ 0 ];
+                    const y = ia * prize.a[ 1 ] + ib * prize.b[ 1 ];
+                    if (x === prize.prize[ 0 ] && y === prize.prize[ 1 ]) {
+                        options.push(ia * 3 + ib);
+                    }
+                }
+            }
+            if (options.length !== 0) {
+                sum += Math.min(...options);
+            }
+        }
+        return sum;
+    }
+    secondPart(input: string) {
+        const prizes = input.split("\n\n")
+            .map(prize => prize.split("\n").map(l => l.split(": ")[ 1 ].split(", ")))
+            .map(([ a, b, prize ]) => ({ a: a.map(o => Number(o.slice(1))), b: b.map(o => Number(o.slice(1))), prize: prize.map(p => 10000000000000 + Number(p.slice(2))) }));
+        let sum = 0;
+        for (const prize of prizes) {
+            // prize.a[ 0 ] * x + prize.b[ 0 ] * y = prize.prize[ 0 ]
+            // prize.a[ 1 ] * x + prize.b[ 1 ] * y = prize.prize[ 1 ]
+            const left = [
+                [ prize.a[ 0 ], prize.b[ 0 ] ],  
+                [ prize.a[ 1 ], prize.b[ 1 ] ]
+            ];
+
+            const right = [
+                prize.prize[ 0 ],
+                prize.prize[ 1 ]  
+            ];
+
+            const solution = mathjs.lusolve(left, right);
+            const [ x, y ] = solution.map(x => Number(x[ 0 ]));
+            if ((x % 1 < 0.001 || x % 1 > 0.999) && (y % 1 > 0.999 || y % 1 < 0.001)) { // Fuck floating point
+                if (x > 0 && y > 0) {
+                    sum += Math.round(x) * 3 + Math.round(y);
+                }
+            }
+        }
+
+        return sum;
+    }
+
+}