advent-of-code/2020/14-Docking_Data/second.js

62 lines
1.3 KiB
JavaScript

import * as fs from 'fs';
const setMask = /mask = ([10X]+)/;
const operation = /mem\[(\d+)] = (\d+)/;
function applyMask(addr, mask) {
let ret = [parseInt(addr).toString(2).padStart(36, '0')];
for (let i=0; i<36; ++i) {
switch (mask.charAt(i)) {
case '1':
ret = ret.map(a => a.substring(0, i) + '1' + a.substring(i+1));
break;
case 'X':
ret = ret.reduce((acc, a) => acc.concat([
a.substring(0, i) + '1' + a.substring(i+1),
a.substring(0, i) + '0' + a.substring(i+1),
]), []);
}
}
return ret.map(a => parseInt(a, 2));
}
function processMasks(lines) {
let ret = new Map();
let mask = '';
lines.forEach(line => {
const m = line.match(setMask);
if (m) {
mask = m[1];
} else {
const o = line.match(operation);
const addr = o[1];
const value = parseInt(o[2]);
applyMask(addr, mask).forEach(r => ret.set(parseInt(r), value));
}
});
return ret;
}
function load(filename) {
return processMasks(fs.readFileSync(filename, 'utf8')
.trim()
.split('\n')
);
}
let example = load('example2');
let input = load('input');
function solve(input) {
let sum = 0;
input.forEach(value => sum += value);
return sum;
}
const exampleOutput = solve(example);
if (exampleOutput !== 208) {
console.log('Example failed with ' + exampleOutput);
process.exit(1); // eslint-disable-line
}
console.log(solve(input));