py_0008_largest_product_in_a_series.py

# Solution of;
# Project Euler Problem 8: Largest product in a series
# https://projecteuler.net/problem=8
# 
# The four adjacent digits in the 1000-digit number that have
# the greatest product are 9 × 9 × 8 × 9 = 5832. 
# 
# 73167176531330624919225119674426574742355349194934
# 96983520312774506326239578318016984801869478851843
# 85861560789112949495459501737958331952853208805511
# 12540698747158523863050715693290963295227443043557
# 66896648950445244523161731856403098711121722383113
# 62229893423380308135336276614282806444486645238749
# 30358907296290491560440772390713810515859307960866
# 70172427121883998797908792274921901699720888093776
# 65727333001053367881220235421809751254540594752243
# 52584907711670556013604839586446706324415722155397
# 53697817977846174064955149290862569321978468622482
# 83972241375657056057490261407972968652414535100474
# 82166370484403199890008895243450658541227588666881
# 16427171479924442928230863465674813919123162824586
# 17866458359124566529476545682848912883142607690042
# 24219022671055626321111109370544217506941658960408
# 07198403850962455444362981230987879927244284909188
# 84580156166097919133875499200524063689912560717606
# 05886116467109405077541002256983155200055935729725
# 71636269561882670428252483600823257530420752963450
#
# the thirteen adjacent digits in the 1000-digit number that have 
# the greatest product. What is the value of this product?
# 
# by lcsm29 http://github.com/lcsm29/project-euler
import timed
# from functools import reduce
# import operator


def fn_brute(n):
    g_product = 0
    for i in range(1001 - n):        
        # tmp = reduce(operator.mul, [int(c) for c in kdigit[i:i + n]], 1)
        # the above was removed because it's slower than the following
        tmp = 1  
        for j in [int(c) for c in kdigit[i:i + n]]:
            tmp *= j
        if max(g_product, tmp) == tmp:
            g_product = tmp
    return g_product


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


if __name__ == '__main__':
    n = 13
    i = 700
    prob_id = 8
    timed.caller(fn_brute, n, i, prob_id)