A combination of all ten digits uniquely is a permutation which can be generated using Algorithm::FastPermute.

So given that the code has to execute for thousands of candidate combinations, it seems it might be better to store all the permutations as the keys of a hash (with value 1 throughout) only once and start accepting candidates to check just by looking up in the hash. If using Linux, an additional optimisation could be to store the pre-calculated set of permutations in a Storable on the /shm (persistent shared memory) device, so that the hash of valid permutations doesn't even need to be calculated between runs of the program and can be loaded directly from persistent shared memory at the beginning of any given run.

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