add 2025

2025/2.1.ts

@@ -0,0 +1,42 @@
+import fs from 'node:fs';
+
+
+const file = fs.readFileSync('./2025/inputs/2').toString();
+const ranges = file.split(",")
+let invalids = 0
+for (const r of ranges) {
+    const [first, last] = r.split("-")
+    processRange(Number(first), Number(last))
+}
+
+function processRange(ogstart: number, ogend: number) {
+    let start = ogstart
+    let end = ogend
+    let startDigitAmount = Math.floor(Math.log10(start))
+    if ((startDigitAmount + 1) % 2 == 1) {
+        start = 10 ** (startDigitAmount + 1)
+        startDigitAmount++
+    }
+    let firstStartHalf = Math.floor(start / (10 ** Math.floor((startDigitAmount + 1) / 2)))
+
+    let endDigitAmount = Math.floor(Math.log10(end))
+    if ((endDigitAmount + 1) % 2 == 1) {
+        end = (10 ** (endDigitAmount)) - 1
+        endDigitAmount--
+    }
+    const firstEndHalf = Math.floor(end / (10 ** Math.floor((endDigitAmount + 1) / 2)))
+
+    for (var i = firstStartHalf; i <= firstEndHalf; i++) {
+        if (Math.floor(Math.log10(start)) % 2 == 0) {
+            continue
+        }
+        const n = Number(i + "" + i)
+        if (ogstart <= n && n <= ogend) {
+            invalids += n
+        }
+
+    }
+
+}
+
+console.log(invalids)