Day 2

2024/02/index.ts

@@ -0,0 +1,48 @@
+const fs = require('fs');
+
+const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');
+
+let safe = 0;
+
+function checkSequence(seq: Array<number>): boolean {
+    let pointer = 0;
+    let prev = seq[pointer];
+    pointer++;
+    let inc = seq[pointer] > prev;
+    while (pointer < seq.length) {
+        const next = seq[pointer];
+        pointer++;
+        if (inc ? next < prev : next > prev) {
+            return false;
+        }
+        const diff = Math.abs(next - prev);
+        if (diff <= 0 || diff > 3) {
+            return false;
+        }
+        prev = next;
+    }
+    return true;
+}
+
+input.split("\n")
+    .forEach((s: string) => {
+        if (s.match('^\s*$')) {
+            return;
+        }
+        const seq = s.split(' ').map((n) => parseInt(n));
+        const isSafe = checkSequence(seq);
+        if (!isSafe) {
+            // Part 2
+            for (let i = 0; i < seq.length; i++) {
+                if (checkSequence([...seq.slice(0, i), ...seq.slice(i + 1)])) {
+                    safe++;
+                    return;
+                }
+            }
+            // End part 2
+            return;
+        }
+        safe++;
+    });
+
+console.log(safe);