This ought to work. I appreciate the elegance of using the hash keys to keep track of a set, without ever updating any hash values (since after all it's only the keys that we need).

The solution I actually ran was kennethk's above, which took over an hour. I suspect this one would take about as long, because even though it doesn't update any counts, it still reads every single character in the file.

Thanks, your solution is running against my file right now.

Launched it right about 22:00 GMT. I estimate it will finish in just under an hour.

In reply to Re^2: Find what characters never appear by Narveson
in thread Find what characters never appear by Narveson

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