Creative Scratchpad

Find the greatest product of five consecutive digits in the 1000-digit number.

    73167176531330624919225119674426574742355349194934     96983520312774506326239578318016984801869478851843     85861560789112949495459501737958331952853208805511     12540698747158523863050715693290963295227443043557     66896648950445244523161731856403098711121722383113     62229893423380308135336276614282806444486645238749     30358907296290491560440772390713810515859307960866     70172427121883998797908792274921901699720888093776     65727333001053367881220235421809751254540594752243     52584907711670556013604839586446706324415722155397     53697817977846174064955149290862569321978468622482     83972241375657056057490261407972968652414535100474     82166370484403199890008895243450658541227588666881     16427171479924442928230863465674813919123162824586     17866458359124566529476545682848912883142607690042     24219022671055626321111109370544217506941658960408     07198403850962455444362981230987879927244284909188     84580156166097919133875499200524063689912560717606     05886116467109405077541002256983155200055935729725     71636269561882670428252483600823257530420752963450

For a change, this is quite a no-brainer. I saved the number in the original format of individual lines as a txt file and used a memStream to read it. Although I could have just as well used fileStream, this is supposed to be a little faster. The sole purpose of the _int function is to shorten the code later on. All the lines are appended to a string (using stringStream didn't result in any benefit), which is then iterated over and for each five numbers a product is calculated and assigned to a midResult variable. If it is bigger than a previously saved value, we replace it with it:

(
    fn _int str =
        nr = str as integer

    fn getNum filePath =
    (
        local result = ""
        local fileStream = memStreamMgr.openFile filePath

        while NOT fileStream.eos() do
            append result (fileStream.readLine())

        memStreamMgr.close fileStream
        result
    )

    local nr = getNum "Z:\Euler\prob8.txt"
    local length = nr.count - 4
    local midResult, result = 0

    for i = 1 to length
        where (midResult = _int(nr[i])*_int(nr[i+1])*_int(nr[i+2])*_int(nr[i+3])*_int(nr[i+4])) > result do
            result = midResult
    result
)

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