Files
advent-of-code/2020/05/part2.js
Nick Thomas f1be11fca8 Add '2020/' from commit 'aaabfa90c9033044d0a9d5fe6776b718711ef46c'
git-subtree-dir: 2020
git-subtree-mainline: ab8f135946
git-subtree-split: aaabfa90c9
2022-01-09 17:06:15 +00:00

37 lines
997 B
JavaScript

const fs = require('fs');
const readline = require('readline');
const readInterface = readline.createInterface({input: fs.createReadStream('input'), console: false});
let seats = []; // [[x,y], [x,y], ...]
readInterface.on('line', function(line) {
let result = line.split('').reduce(function(sp, char) {
const halfX = Math.floor((1 + sp[2] - sp[0]) / 2);
const halfY = Math.floor((1 + sp[3] - sp[1]) / 2);
switch(char) {
case 'F': sp[3] -= halfY; break;
case 'B': sp[1] += halfY; break;
case 'L': sp[2] -= halfX; break;
case 'R': sp[0] += halfX; break;
};
return sp;
}, [0,0,7,127]);
seats.push([result[0], result[1]]);
});
readInterface.on('close', function(line) {
let seatIDs = new Set( seats.map((seat) => seat[1]*8 + seat[0]) );
for (x=0; x<8; x++) {
for(y=0; y<128; y++) {
let seatID = y*8+x;
if (!seatIDs.has(seatID) && seatIDs.has(seatID-1) && seatIDs.has(seatID+1)) {
console.log(seatID);
}
}
}
});