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- #!/usr/bin/ruby
- # Author: Daniel "Trizen" Șuteu
- # License: GPLv3
- # Website: https://github.com/trizen
- # An irrational decimal fraction is created by concatenating the positive integers:
- # 0.123456789101112131415161718192021...
- # It can be seen that the 12th digit of the fractional part is 1.
- # If dn represents the nth digit of the fractional part, find the value of the following expression.
- # d1 × d10 × d100 × d1000 × d10000 × d100000 × d1000000
- # https://projecteuler.net/problem=40
- # Runtime: 59.832s
- var str = ''
- for i in (1..Inf) {
- str += i
- str.len >= 1000000 && break
- }
- var prod = 1
- for i in (0..6) {
- prod *= str.char(10**i - 1)
- }
- say prod
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