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74 lines
2.0 KiB
74 lines
2.0 KiB
width = nil
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map = {}
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for line in io.lines(arg[1]) do
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if not width then
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width = #line
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end
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for char in line:gmatch(".") do
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table.insert(map, char)
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end
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end
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function reachable_keys(map, pos_y, pos_x, keys, dist)
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local cell = map[width * pos_y + pos_x]
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if cell == "@" then
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cell = "."
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end
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if cell == "." then
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map[width * pos_y + pos_x] = "#"
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reachable_keys(map, pos_y + 1, pos_x, keys, dist + 1)
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reachable_keys(map, pos_y - 1, pos_x, keys, dist + 1)
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reachable_keys(map, pos_y, pos_x + 1, keys, dist + 1)
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reachable_keys(map, pos_y, pos_x - 1, keys, dist + 1)
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elseif string.byte(cell) >= 97 and string.byte(cell) <= 122 then
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table.insert(keys, {key=cell, y=pos_y, x=pos_x, dist=dist})
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end
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return keys
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end
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function find_paths(map, pos_y, pos_x)
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local keys = reachable_keys({table.unpack(map)}, pos_y, pos_x, {}, 0)
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local paths = {}
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for _, key in ipairs(keys) do
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--print(key.key, key.dist)
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local open_map = {table.unpack(map)}
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open_map[width * pos_y + pos_x] = "."
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open_map[width * key.y + key.x] = "@"
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for i, x in ipairs(open_map) do
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if x:lower() == key.key then
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open_map[i] = "."
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break
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end
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end
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local path = find_paths(open_map, key.y, key.x)
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if #path == 0 then
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table.insert(paths, {path={key.key}, dist=key.dist})
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else
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for _, p in ipairs(path) do
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table.insert(p.path, key.key)
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p.dist = p.dist + key.dist
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table.insert(paths, p)
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end
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end
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end
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return paths
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end
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pos_y = nil
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pos_x = nil
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for i, x in ipairs(map) do
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if x == "@" then
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pos_y = i // width
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pos_x = i % width
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break
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end
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end
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paths = find_paths(map, pos_y, pos_x)
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smallest = nil
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for _, path in ipairs(paths) do
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if not smallest or smallest.dist > path.dist then
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smallest = path
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end
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end
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print(table.concat(smallest.path, ","), smallest.dist)
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