A vampire number is a non-negative number that can be factored into two
numbers (fangs) each with half as many digits as the original where the
two factors contain all the digits of the original, in any order. One but
not both fangs may have trailing zeros.
For example 1260 = 21*60, 1395 = 15*93, 1435 = 35*41,
1530 = 30*51, etc..
Print all the vampire numbers from 1 to 1,000,000 inclusive,
each on their own line.
Be careful with the algorithmic complexity of your solution to avoid