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Fraction reduction: Difference between revisions
m
→{{header|Haskell}}
Line 1,362:
validIntegers :: [Int] -> [Int]
validIntegers xs = [x | x <- xs, not $ hasZeros x, hasUniqueDigits x]
where
where
ds = digits 10 n
ul = nub ds
possibleFractions :: [Int] -> [Fraction]
Line 1,378 ⟶ 1,375:
, n < d
, gcd n d /= 1 ]
commonDigits (n1, n2) = digits 10 n1 `intersect` digits 10 n2▼
dropDigit d = digitsToIntegral . delete d . digits 10▼
digits :: Integral a => a -> a -> [a]
Line 1,394 ⟶ 1,385:
findReduction z@(n1, d1) = foldr f [] $ commonDigits z
where
▲ commonDigits (n1, n2) = digits 10 n1 `intersect` digits 10 n2
decimal = realToFrac n1 / realToFrac d1
f x r | decimalWithDrop == decimal = (z, (n2, d2), x) : r
| otherwise = r
where
▲ dropDigit d = digitsToIntegral . delete d . digits 10
n2 = dropDigit x n1
d2 = dropDigit x d1
Line 1,405 ⟶ 1,398:
findReductions = (findReduction =<<) . possibleFractions
printf "There are %d %d-digit fractions of which:\n" (length xs) n
mapM_ (uncurry (printf "%5d have %d's omitted\n")) (countReductions xs) >> printf "\n"
Line 1,417 ⟶ 1,410:
main :: IO ()
main = do
mapM_ (\g -> mapM_
mapM_ (uncurry
where
groups = [ findReductions [10^1..99], findReductions [10^2..999]
| |||