# Copyright © 2004-2013 Brent Fulgham
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# The Computer Language Benchmarks Game
# http://benchmarksgame.alioth.debian.org

# transliterated from Mario Pernici's Python program
# contributed by Rick Branson

# http://benchmarksgame.alioth.debian.org/u64q/program.php?test=pidigits&lang=yarv&id=3

def pidigits(n_prime)
  sum = 0

  i = k = ns = 0
  k1 = 1
  n,a,d,t,u = [1,0,1,0,0]

  loop do
    k += 1
    t = n<<1
    n *= k
    a += t
    k1 += 2
    a *= k1
    d *= k1
    if a >= n
      t,u = (n*3 +a).divmod(d)
      u += n
      if d > u
        ns = ns*10 + t
        i += 1
        if i % 10 == 0
          sum ^= ns/1000
          ns = 0
        end
        break if i >= n_prime

        a -= d*t
        a *= 10
        n *= 10
      end
    end
  end

  sum
end

def harness_input
  5000
end

def harness_sample(input)
  pidigits(input)
end

def harness_verify(output)
  output == 1007389
end

require 'bench9000/harness'