Day 22 and 23

2024/22/index.ts

@@ -0,0 +1,59 @@
+const fs = require('fs');
+
+const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');
+
+function createSecret(secret: bigint) {
+    secret = ((secret << 6n) ^ secret) % 16777216n;
+    secret = ((secret >> 5n) ^ secret) % 16777216n;
+    return ((secret << 11n) ^ secret) % 16777216n;
+}
+
+
+let sum = 0n;
+
+const changeMap: { [key: string]: Array<number> } = {};
+
+input.split("\n").forEach((s: string, index: number) => {
+    let seed = BigInt(parseInt(s));
+    let seedStr = ''+seed;
+    const changes = [];
+    for (let i = 0; i < 2000; i++) {
+        const newSeed = createSecret(seed);
+        const newSeedStr = ''+newSeed;
+        const lastDig = parseInt(newSeedStr[newSeedStr.length - 1]);
+        const diff = lastDig - parseInt(seedStr[seedStr.length - 1]);
+        changes.push(diff);
+        if (i > 3) {
+            changes.shift();
+            const key = changes.join(',');
+            if (!changeMap[key]) {
+                changeMap[key] = [];
+            }
+            if (!changeMap[key][index]) {
+                changeMap[key][index] = lastDig;
+            }
+        }
+        seed = newSeed;
+        seedStr = newSeedStr;
+    }
+    sum += seed;
+});
+
+let highest: null|number = null;
+let highestSeq: null|string = null;
+
+for (let seq in changeMap) {
+    const prices = changeMap[seq];
+    let priceSum = 0;
+    prices.forEach((p) => {
+        if (p) {
+            priceSum += p;
+        }
+    });
+    if (!highest || priceSum > highest) {
+        highest = priceSum;
+        highestSeq = seq;
+    }
+}
+
+console.log(sum, highest, highestSeq);

2024/23/index.ts

@@ -0,0 +1,30 @@
+const fs = require('fs');
+
+const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');
+
+const connections: { [key: string]: Array<string> }= {};
+
+input.split("\n").forEach((conn: string) => {
+    const [c1, c2] = conn.split('-');
+    connections[c1] = [c2, ...(connections[c1] || [])]
+    connections[c2] = [c1, ...(connections[c2] || [])]
+});
+
+const tCs = new Set;
+
+for (let key in connections) {
+    const conns = connections[key];
+    if (key.startsWith('t')) {
+        conns.forEach((c2) => {
+            connections[c2].forEach((c3) => {
+                if (connections[c3].includes(key)) {
+                    const arr = [key, c2, c3];
+                    arr.sort();
+                    tCs.add(arr.join(','));
+                }
+            })
+        })
+    }
+}
+
+console.log(tCs, tCs.size);