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  1. Prepare
  2. Algorithms
  3. Bit Manipulation
  4. AND Product
  5. Discussions

AND Product

  • jmcparland
     + 0 comments

    Haskell

    I'm kind of surprised to see implementations that AND over the list in the discussion; a Haskell foldl1 (.&.) [a..b] (basically the same thing) would often timeout.

    module Main where

import Data.Bits (shiftL, shiftR, (.&.))
import Control.Monad (replicateM_)

solve :: [Integer] -> Integer
solve [a, b] = commonPrefix a b
  where
    commonPrefix x y
        | x == y = x
        | otherwise = commonPrefix (x `shiftR` 1) (y `shiftR` 1) `shiftL` 1

main :: IO ()
main = do
    cases <- readLn :: IO Int
    replicateM_ cases $ do
        getLine >>= print . solve . map read . words