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Diffstat (limited to 'challenge-147/sgreen/python/ch-1.py')
| -rwxr-xr-x | challenge-147/sgreen/python/ch-1.py | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/challenge-147/sgreen/python/ch-1.py b/challenge-147/sgreen/python/ch-1.py new file mode 100755 index 0000000000..1b77f58482 --- /dev/null +++ b/challenge-147/sgreen/python/ch-1.py @@ -0,0 +1,50 @@ +#!/usr/bin/env python + +import math + + +def is_prime(number): + # Return true or false if the number is a prime + if number < 2: + return False + + for i in range(2, int(math.sqrt(number)) + 1): + if number % i == 0: + return False + + # It's a prime + return True + + +def is_trunc_prime(number): + # Return true or false if the number and all it's left truncated + # parts is a prime. Start with the smallest figure first + n = str(number) + + if '0' in n: + # A left-truncatable prime cannot contain a zero + return False + + for i in range(len(n), 0, -1): + if not is_prime(int(n[i - 1:])): + return False + + return True + + +def main(): + solutions = [] + number = 1 + + # Keep increasing number by one until we have twenty truncated prime + # numbers + while len(solutions) < 20: + if is_trunc_prime(number): + solutions.append(number) + number += 1 + + print(*solutions, sep=', ') + + +if __name__ == '__main__': + main() |
