Project Euler : Problem 18

dailycoding18.hs

-- Project Euler : Problem 18

triangle :: [[Int]]
triangle = [
           [75],
           [95, 64],
           [17, 47, 82],
           [18, 35, 87, 10],
           [20, 04, 82, 47, 65],
           [19, 01, 23, 75, 03, 34],
           [88, 02, 77, 73, 07, 63, 67],
           [99, 65, 04, 28, 06, 16, 70, 92],
           [41, 41, 26, 56, 83, 40, 80, 70, 33],
           [41, 48, 72, 33, 47, 32, 37, 16, 94, 29],
           [53, 71, 44, 65, 25, 43, 91, 52, 97, 51, 14],
           [70, 11, 33, 28, 77, 73, 17, 78, 39, 68, 17, 57],
           [91, 71, 52, 38, 17, 14, 91, 43, 58, 50, 27, 29, 48],
           [63, 66, 04, 68, 89, 53, 67, 30, 73, 16, 69, 87, 40, 31],
           [04, 62, 98, 27, 23, 09, 70, 98, 73, 93, 38, 53, 60, 04, 23]
           ]

distance :: [[Int]] -> Int
distance [] = 0
distance [x:[]] = x
distance x = root + max (distance left) (distance right)
    where root  = head $ head x
          left  = map init $ tail x
          right = map tail $ tail x

main = print $ distance triangle

-- 1074
-- ./dailycoding18  0.00s user 0.01s system 65% cpu 0.010 total