blob: 68fcc004c4bc4898a7e97558c0ce5e05e41197c4 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
------
-- Largest exponential
-- Problem 99
--
-- Comparing two numbers written in index form like 211 and 37 is not difficult,
-- as any calculator would confirm that 211 = 2048 < 37 = 2187.
-- However, confirming that 632382518061 > 519432525806 would be much more difficult,
-- as both numbers contain over three million digits.
-- Using base_exp.txt (right click and 'Save Link/Target As...'), a 22K text file
-- containing one thousand lines with a base/exponent pair on each line, determine which
-- line number has the greatest numerical value.
-- NOTE: The first two lines in the file represent the numbers in the example given above.
------
import Data.List(elemIndex, maximumBy)
import Data.Maybe(fromJust)
main = do
content <- readFile "../data/099_base_exp.txt"
let base_exp = map (map (\s -> read s :: Integer) . split ',') $ lines content
print (fst $ maximumBy (\(i, be1) (j, be2) -> compare be1 be2)
$ map (\(i, be) -> (i, head be ^ last be)) $ zip [1..] base_exp)
split :: Eq a => a -> [a] -> [[a]]
split _ [] = [[]]
split delim str =
let (before, remainder) = span (/= delim) str
in before : case remainder of [] -> []
x -> split delim $ tail x
|
