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1 parent cb511a0 commit 72b0f21c8c8df041b1dab4b1478ae72a0fae45c3 @ndbroadbent committed Oct 13, 2010
Showing with 67 additions and 0 deletions.
  1. +67 −0 8/solution.rb
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+#!/usr/bin/env ruby
+# coding: utf-8
+# -----------------------------------------
+# | A solution to a Project Euler problem |
+# -----------------------------------------
+require 'rubygems'
+require 'pp'
+problem_no = File.dirname(File.expand_path(__FILE__)).split('/').last
+puts "=== Solving Project Euler problem ##{problem_no}\n\n"
+question = %Q{
+
+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
+
+}
+puts "? #{question.strip}\n\n"
+# --------------------------------------------------------------------
+
+number = %Q"73167176531330624919225119674426574742355349194934
+96983520312774506326239578318016984801869478851843
+85861560789112949495459501737958331952853208805511
+12540698747158523863050715693290963295227443043557
+66896648950445244523161731856403098711121722383113
+62229893423380308135336276614282806444486645238749
+30358907296290491560440772390713810515859307960866
+70172427121883998797908792274921901699720888093776
+65727333001053367881220235421809751254540594752243
+52584907711670556013604839586446706324415722155397
+53697817977846174064955149290862569321978468622482
+83972241375657056057490261407972968652414535100474
+82166370484403199890008895243450658541227588666881
+16427171479924442928230863465674813919123162824586
+17866458359124566529476545682848912883142607690042
+24219022671055626321111109370544217506941658960408
+07198403850962455444362981230987879927244284909188
+84580156166097919133875499200524063689912560717606
+05886116467109405077541002256983155200055935729725
+71636269561882670428252483600823257530420752963450".strip.gsub(/[\n ]/,'')
+
+max = 0
+while number.size >= 5
+ p = number[0,5].split('').inject(1){|r,n| r * n.to_i }
+ max = p if p > max
+ number = number[1, number.size]
+end
+
+puts max

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