ProjectEuler #8

gistfile1.rb

number_ary = []
number_string = []
ans = []

number = open("./problem8_number")

while number_data = number.gets
  number_ary <<  number_data.chomp
end

number_string = number_ary.join

(0..995).each do |num|
  number_temp = number_string[num..num+4]
    # num を先頭に5個取り出すなら number_string[num, 5] の方が分かりやすい
  number_temp = number_temp.split("").map{|e| e.to_i}
  number_temp = number_temp.inject(1){|prd, e| prd *= e}
  ans << number_temp
end

ans2 = []
ary = number_string.split("").map{|i| i.to_i }
(0..995).each do |idx|
  ans2 << ary[idx, 5].inject(1){|prd,e| prd *= e }
end

p ans.sort.last
p ans2.max