You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

49 lines
1.0 KiB
JavaScript

4 years ago
const fs = require("fs");
let [rules, messages] = fs
.readFileSync("input", "utf-8")
.trim()
.split("\n\n")
.map((part) => part.split("\n"));
rules = rules
.map((line) => line.split(": "))
.map(([num, rule]) => [parseInt(num), rule])
.sort((a, b) => a[0] - b[0])
.map(([_, rule]) => rule);
console.log(rules);
console.log("=");
// console.log(messages);
function getRegex(idx) {
const rule = rules[idx];
if (rule.startsWith('"')) {
return rule.slice(1, rule.length - 1);
}
let regex = "";
let multiple = false;
for (const symbol of rule.split(" ")) {
if (symbol === "|") {
regex = "(" + regex + "|";
multiple = true;
} else {
regex = regex + getRegex(parseInt(symbol));
}
}
regex = multiple ? regex + ")" : regex;
rules[idx] = '"' + regex + '"';
return regex;
}
const regex = new RegExp(`^${getRegex(0)}$`);
console.log(rules);
console.log(regex);
let sum = 0;
for (const message of messages) {
if (regex.test(message)) sum++;
}
console.log(sum);