Day 10

2024/10/index.ts

@@ -0,0 +1,62 @@
+const fs = require('fs');
+
+const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');
+
+interface Coord { x: number, y: number };
+
+const topo: Array<string> = input.split("\n").slice(0, -1);
+
+const height = topo.length;
+const width = topo[0].length;
+
+
+let sum = 0;
+
+function getScore({ x, y }: Coord, height = 0, trail: Array<Coord> = [], peaks: Array<string> = []): number {
+    let score = 0;
+
+    const nextHeight = height + 1;
+    [
+        { x, y: y - 1 },
+        { x, y: y + 1 },
+        { x: x - 1, y },
+        { x: x + 1, y },
+    ].forEach((coord) => {
+        if (!topo[coord.y] || !topo[coord.y][coord.x]) {
+            return;
+        }
+        if (parseInt(topo[coord.y][coord.x]) === nextHeight) {
+            if (nextHeight === 9) {
+                const coordString = `${coord.x},${coord.y}`;
+                if (!peaks.includes(coordString)) {
+                    score += 1;
+                    // peaks.push(coordString); // Only for Part 1
+                }
+            } else {
+                score += getScore(coord, nextHeight, [...trail, { x, y }], peaks);
+            }
+        }
+    });
+
+    return score;
+}
+
+let y = 0;
+let x = 0;
+for (let i = 0; i <= input.length; i++) {
+    const char = input[i];
+    if (char === "\n") {
+        y++;
+        x = 0;
+        continue;
+    }
+
+    if (char === '0') {
+        const score = getScore({ x, y });
+        sum += score;
+    }
+
+    x++;
+}
+
+console.log(sum);