68 lines
1.2 KiB
Typst
68 lines
1.2 KiB
Typst
#import "/src/utils.typ": *
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#let offsets = (
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(-1, 0),
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(0, -1),
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(1, 0),
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(0, 1)
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)
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#let in-grid(w, h, x, y) = {
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return 0 <= x and x < w and 0 <= y and y < h
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}
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#let count-paths(grid, w, h, ox, oy) = {
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let tails = ()
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let in-grid = in-grid.with(w, h)
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let to-visit = ((ox, oy),)
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while to-visit.len() != 0 {
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let (x, y) = to-visit.remove(0)
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let v = grid.at(y).at(x)
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for (dx, dy) in offsets {
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let (x2, y2) = (x + dx, y + dy)
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if not in-grid(x2, y2) {
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continue
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}
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let v2 = grid.at(y2).at(x2)
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if v2 == v + 1 {
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let pos2 = (x2, y2)
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if v2 == 9 {
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if pos2 not in tails {
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tails.push(pos2)
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}
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} else {
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to-visit.push(pos2)
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}
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}
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}
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}
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return tails.len()
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}
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#let solve(input) = {
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let grid = input.split("\n").map(l => l.clusters().map(int))
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let w = grid.first().len()
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let h = grid.len()
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let count-paths = count-paths.with(grid, w, h)
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let total = 0
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for y in range(h) {
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for x in range(w) {
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if grid.at(y).at(x) == 0 {
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total += count-paths(x, y)
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}
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}
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}
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return total
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}
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#show-puzzle(
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10, 1,
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solve,
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example: 36
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) |