Problem 1826. Find vampire numbers
A vampire number is a number v that is the product of two numbers x and y such that the following conditions are satisfied:
- at most one of x and y are divisible by 10;
- x and y have the same number of digits; and
- The digits in v consist of the digits of x and y (including any repetitions).
If these conditions are met, x and y are known as "fangs" of v. For example, 1260 is a vampire number because 1260 = 21*60, so 21 and 60 are the fangs.
Write a function that returns all the vampire numbers in a given array. The output is a vector.
Example: disp(find_vampire(1000:2000) 1260 1395 1435 1530 1827
See also: Problem 1825. Find all vampire fangs and Problem 1804. Fangs of a vampire number.
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2 Comments
Are you sure about the first rule? It doesn't seem necessary according to https://oeis.org/A014575.
The problem is really fun.
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