# -.- coding: latin-1 -.- """ Champernowne's constant Problem 40 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 """ from __future__ import print_function def solution(): """Returns >>> solution() 210 """ constant = [] i = 1 while len(constant) < 1e6: constant.append(str(i)) i += 1 constant = "".join(constant) return ( int(constant[0]) * int(constant[9]) * int(constant[99]) * int(constant[999]) * int(constant[9999]) * int(constant[99999]) * int(constant[999999]) ) if __name__ == "__main__": print(solution())