aoc/2020/05/part2.js

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JavaScript
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2020-12-06 14:25:47 +00:00
const fs = require('fs');
const data = fs.readFileSync('input.txt', 'utf-8');
const lines = data.split('\n');
let seats = []
// who really needs semicolons anyway
for (let i = 0; i < lines.length; i++) {
let line = lines[i]
let rowCode = line.substring(0, 7).replace(/F/g, "0").replace(/B/g, "1")
let colCode = line.substring(7).replace(/L/g, "0").replace(/R/g, "1")
// another excuse to flex that recursive muscle
function getIndexFromBSP (BSP, min, max) {
if (BSP.length != 1) {
[min, max] = getIndexFromBSP (BSP.substring(0, BSP.length-1), min, max)
}
switch (BSP[BSP.length-1]) {
case '0':
max = Math.floor((min + max) / 2)
break
case '1':
min = Math.ceil((min + max) / 2)
break
default:
console.log("something went wrong")
}
return [min, max]
}
let row = getIndexFromBSP(rowCode, 0, 127)[0]
let col = getIndexFromBSP(colCode, 0, 7)[0]
seats [row] = seats[row] || []
seats [row] [col] = (row*8)+col
}
// i just scrolled thru and found the one empty seat
console.log(seats.filter(row => row.length>7))