Day 7

.vscode/settings.json

@@ -1,5 +1,8 @@
 {
     "deno.enable": true,
     "deno.lint": true,
-    "deno.unstable": false
+    "deno.unstable": false,
+    "deno.enablePaths": [
+        "./day3"
+    ]
 }

README.md

@@ -31,4 +31,9 @@ I'll probably try to vary languages a bit to get some variety.
 **Note**: Here begin the optimisations! (some people got away with brute force, I decided not to even go there).
 
 ### [Day 6](day6/)
-**Language**: Haskell
+**Language**: Haskell
+
+### [Day 7](day7/)
+**Language**: JavaScript (Node)
+
+**Note**: Yes, I used JSDoc for type-hints. But I think only insane people use JavaScript without JSDoc.

day7/eg.txt

@@ -0,0 +1,5 @@
+32T3K 765
+T55J5 684
+KK677 28
+KTJJT 220
+QQQJA 483

day7/solution.js

@@ -0,0 +1,85 @@
+const fs = require("fs/promises");
+
+const order = ["A", "K", "Q", "J", "T", "9", "8", "7", "6", "5", "4", "3", "2"];
+const newOrder = ["A", "K", "Q", "T", "9", "8", "7", "6", "5", "4", "3", "2", "J"];
+
+/**
+ * @param {string[]} hand
+ * @param {boolean} useJoker
+ */
+function handType(hand, useJoker = false) {
+    function eq(v) {
+        return c => c === v || useJoker && c === "J";
+    }
+    const s = new Set(useJoker ? hand.filter(c => c !== "J") : hand);
+    if (s.size === 1 || s.size === 0) { // 0 if JJJJJ and useJoker == true
+        return 0;
+    } else if (s.size === 2) {
+        let m = -1;
+        for (const v of s.values()) {
+            const count = hand.filter(eq(v)).length;
+            if (count > m) m = count;
+        }
+        if (m === 4) {
+            return 1;
+        }
+        return 2;
+    } else if (s.size === 3) {
+        let m = -1;
+        for (const v of s.values()) {
+            const count = hand.filter(eq(v)).length;
+            if (count > m) m = count;
+        }
+        if (m === 3) {
+            return 3;
+        }
+        return 4;
+    } else if (s.size === 4) {
+        return 5;
+    }
+    return 6;
+}
+
+/**
+ * @param {string[]} h1
+ * @param {string[]} h2
+ * @param {boolean} useJoker
+ */
+function cmpHands(h1, h2, useJoker = false) {
+    const [t1, t2] = [handType(h1, useJoker), handType(h2, useJoker)];
+    if (t1 !== t2) return t1 - t2;
+    for (let idx = 0; idx < h1.length; idx++) {
+        const [v1, v2] = [h1[idx], h2[idx]];
+        if (v1 !== v2) {
+            return useJoker ? newOrder.indexOf(v1) - newOrder.indexOf(v2)
+                : order.indexOf(v1) - order.indexOf(v2);
+        }
+    }
+    return 0;
+}
+
+/**
+ * @param {{hand: string[], bid: number}[]} hands
+ */
+function totalWinnings(hands) {
+    return hands.map((h, idx) => h.bid * (idx + 1))
+        .reduce((p, c) => p + c)
+}
+
+async function main() {
+    const lines = await fs.readFile("input.txt", {encoding: "utf8"})
+        .then(s => s.split("\n"));
+    const hands = lines.map(l => {
+        const [h, b] = l.split(" ");
+        return {
+            hand: h.split(""),
+            bid: Number(b)
+        };
+    });
+    hands.sort((h1, h2) => cmpHands(h2.hand, h1.hand));
+    console.log("Part 1:", totalWinnings(hands));
+    hands.sort((h1, h2) => cmpHands(h2.hand, h1.hand, true));
+    console.log("Part 2:", totalWinnings(hands));
+}
+
+main();