up to day 6

2020/5.js

@@ -0,0 +1,58 @@
+const fs = require('fs');
+const input = fs.readFileSync('5.txt').toString().split('\n');
+
+function bsp(lower, upper, partitions)
+{    
+    const current = partitions.shift(); // like pop but begining
+    const diff = upper - lower;
+
+    if (current == 'F' || current == 'L') // lower half
+    {
+        if (partitions.length == 0) return lower;
+        upper = upper - Math.floor(diff / 2);
+    } else 
+    {
+        if (partitions.length == 0) return upper;
+        lower = lower + Math.floor(diff / 2);
+    }
+
+    return bsp(lower, upper, partitions);
+}
+
+let takenSeats = [];
+
+let highestID = 0;
+
+for (let seat of input)
+{
+    const front = seat.substr(0, 7).split(''); // 8 partitions of 128
+    const left = seat.substr(7, 9).split(''); // 3 partitions of 8
+    
+    const row = bsp(0, 127, front);
+    const col = bsp(0, 7, left);
+
+    const id = (row * 8) + col;
+
+    takenSeats.push(id);
+
+    if (id > highestID) highestID = id;
+}
+
+console.log(`Part 1, Highest seat ID: ${highestID}`);
+
+let takenSeatsUnique = [...new Set(takenSeats)];
+takenSeatsUnique.sort((a, b) => { return a - b});
+
+console.log(JSON.stringify(takenSeatsUnique));
+let seat;
+
+for (let i = 5; i < takenSeatsUnique.length; i++)
+{
+    if (takenSeatsUnique[i] != takenSeatsUnique[i - 1] + 1)
+    {
+        seat = takenSeatsUnique[i] - 1;
+        break;
+    }
+}
+
+console.log(`Part 2, Empty seat: ${seat}`);