aoc/2024/09/solution2.js
2024-12-10 09:04:17 +00:00

51 lines
1.2 KiB
JavaScript

const input = (await Bun.file(Bun.argv[2]).text()).trim()
const files = [];
const spaces = [[], [], [], [], [], [], [], [], [], [], ];
let pos = 0;
for (let i = 0; i < input.length; i++ ) {
const size = parseInt(input[i])
if (size == 0) continue
if (i % 2 == 0) {
files.push({size, id: i / 2, start: pos,})
} else {
spaces[size].push(pos)
}
pos += size;
}
for (let i = files.length - 1; i >= 0; i--) {
const file = files[i]
const fitspaces = [];
for (let size = files[i].size; size <= 9; size ++ ) {
if (spaces[size].length == 0) {
continue
}
const start = spaces[size][0]
if (start > file.start) {
continue
}
fitspaces.push({size, start})
}
if (fitspaces.length == 0) continue
fitspaces.sort((a, b) => a.start > b.start)
const space = fitspaces[0]
files[i].start = space.start;
spaces[space.size].shift()
const newspacestart = space.start + files[i].size
const newspacesize = space.size - file.size
if (newspacesize == 0) continue
spaces[newspacesize].push(newspacestart)
spaces[newspacesize].sort((a, b) => a > b)
}
const checksum = fs => fs.reduce((acc, current) =>
acc + (current.id * current.size * (current.start + (current.size - 1) / 2)),
0)
console.log(checksum(files))