60 lines
1.3 KiB
JavaScript
60 lines
1.3 KiB
JavaScript
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const input = (await Bun.file("input.txt").text()).trim()
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// const input = "2933133121414131402";
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/*
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* 0123456789
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* 0..1.....2
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* 02.1
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* 021
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*/
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const files = [];
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const spaces = [[], [], [], [], [], [], [], [], [], [], ];
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let pos = 0;
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for (let i = 0; i < input.length; i++ ) {
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const size = parseInt(input[i])
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if (size == 0) continue
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if (i % 2 == 0) {
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files.push({size, id: i / 2, start: pos,})
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} else {
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spaces[size].push(pos)
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}
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pos += size;
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}
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for (let i = files.length - 1; i >= 0; i--) {
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const file = files[i]
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const fitspaces = [];
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for (let size = files[i].size; size <= 9; size ++ ) {
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if (spaces[size].length == 0) {
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continue
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}
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const start = spaces[size][0]
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if (start > file.start) {
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continue
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}
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fitspaces.push({size, start})
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}
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if (fitspaces.length == 0) continue
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fitspaces.sort((a, b) => a.start > b.start)
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const space = fitspaces[0]
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files[i].start = space.start;
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spaces[space.size].shift()
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const newspacestart = space.start + files[i].size
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const newspacesize = space.size - file.size
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if (newspacesize == 0) continue
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spaces[newspacesize].push(newspacestart)
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spaces[newspacesize].sort((a, b) => a > b)
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}
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const checksum = fs => fs.reduce((acc, current) =>
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acc + (current.id * current.size * (current.start + (current.size - 1) / 2)),
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0)
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console.log(checksum(files))
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