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#!/opt/local/bin/lua
--
-- See ../README.md
--
--
-- Run as: lua ch-2.lua < input-file
--
function substrings (n, m, prefix, max)
if n : len () == 0 then
if prefix > -1 and prefix < max and prefix % m == 0 then
return 1
else
return 0
end
end
local fc = tonumber (n : sub (1, 1))
local tail = n : sub (2)
local n_prefix
if prefix == -1 then
n_prefix = fc
else
n_prefix = 10 * prefix + fc
end
return substrings (tail, m, n_prefix, max) +
substrings (tail, m, prefix, max)
end
for line in io . lines () do
local _, _, n, m = line : find ("([0-9]+)%s+([0-9]+)")
print (substrings (n, tonumber (m), -1, tonumber (n)))
end
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