Add 2020 day 5

2020/day5/day5.js

@@ -0,0 +1,24 @@
+#!/bin/node
+
+const fs = require('fs');
+
+fs.readFile('input.txt', (err, data) => {
+    const seats = data.toString()
+        .split('\n')
+        .filter(l => l.length > 0)
+        .map(s => s.replaceAll(/[BR]/g, '1')
+            .replaceAll(/[FL]/g, '0'))
+        .map(s => parseInt(s, 2));
+
+    console.log('Highest seat:', seats.reduce((a, v) => v > a ? v : a, -1));
+
+    seats.sort();
+    for (let i = 0; i < seats.length; i++) {
+        const seat = seats[i];
+        const nextSeat = seats[i + 1];
+        if (nextSeat - seat === 2) {
+            console.log('Your seat:', seat + 1);
+            break;
+        }
+    }
+});