104 lines
2.8 KiB
TypeScript
104 lines
2.8 KiB
TypeScript
import fs from "node:fs";
|
|
import { printTime, now } from "../util";
|
|
|
|
const test = false;
|
|
|
|
const data = fs.readFileSync(
|
|
test ? "./inputs/testinput" : "./inputs/input",
|
|
"utf8"
|
|
);
|
|
|
|
let timer = now.instant();
|
|
console.log(
|
|
"part one:",
|
|
data
|
|
.split("\n")
|
|
.slice(0, -1)
|
|
.reduce((coll, curr, index, array) => {
|
|
// 2D string matching is a pain. Let's turn it into a 1D problem!
|
|
// create the down rows
|
|
curr.split("").forEach((s, i) => {
|
|
coll[i] = coll[i] ? coll[i] + s : s;
|
|
});
|
|
// create the down-left-diagonals
|
|
curr.split("").forEach((s, i) => {
|
|
coll[i + array.length + index] = coll[i + array.length + index]
|
|
? coll[i + array.length + index] + s
|
|
: s;
|
|
});
|
|
// create the down-right-diagonals
|
|
curr.split("").forEach((s, i) => {
|
|
coll[array.length * 4 + index - i - 2] = coll[
|
|
array.length * 4 + index - i - 2
|
|
]
|
|
? coll[array.length * 4 + index - i - 2] + s
|
|
: s;
|
|
});
|
|
// include the original crosses
|
|
return [...coll, curr];
|
|
}, Array.from({ length: test ? 10 + (10 * 4 - 2) : 140 + 140 * 4 - 2 }) as string[])
|
|
.reduce((total, curr) => {
|
|
// and now just do some regexes over the set of 1D strings
|
|
let matchesForward = curr.match(/XMAS/g);
|
|
let matchesBackward = curr.match(/SAMX/g);
|
|
if (matchesForward) {
|
|
total += matchesForward.length;
|
|
}
|
|
if (matchesBackward) {
|
|
total += matchesBackward.length;
|
|
}
|
|
return total;
|
|
}, 0),
|
|
printTime(now.instant().since(timer))
|
|
);
|
|
|
|
timer = now.instant();
|
|
console.log(
|
|
"part two:",
|
|
data
|
|
.split("\n")
|
|
.slice(0, -1)
|
|
.reduce((coll, curr, index, array) => {
|
|
if (index === 0 || index === array.length - 1) {
|
|
// we can entirely skip the first and last rows, since there's no way to get a cross started
|
|
return coll;
|
|
}
|
|
// look for A's
|
|
curr.split("").forEach((s, i, a) => {
|
|
if (i === 0 || i === a.length - 1) {
|
|
// same as above, edges are useless
|
|
return;
|
|
}
|
|
if (s === "A") {
|
|
// 1 2
|
|
// A
|
|
// 3 4
|
|
coll = [
|
|
...coll,
|
|
array[index - 1][i - 1] +
|
|
array[index - 1][i + 1] +
|
|
array[index + 1][i - 1] +
|
|
array[index + 1][i + 1],
|
|
];
|
|
}
|
|
});
|
|
return coll;
|
|
}, [] as string[])
|
|
.reduce((coll, curr) => {
|
|
// we could have just done this check above,
|
|
// but it's a little more clear, although slower,
|
|
// to iterate again.
|
|
switch (curr) {
|
|
case "MSMS":
|
|
case "SSMM":
|
|
case "SMSM":
|
|
case "MMSS":
|
|
coll += 1;
|
|
default:
|
|
break;
|
|
}
|
|
return coll;
|
|
}, 0),
|
|
printTime(now.instant().since(timer))
|
|
);
|