Everyone else has offered good advice on the array processing, however it may also be worth asking how you are reading the data from the file. At one million lines of data, improvements in transferring the data from file to memory may also cut your runtime

If you spot any bugs in my solutions, it's because I've deliberately left them in as an exercise for the reader! :-)

In reply to Re: How to improve this data structure? by space_monk
in thread How to improve this data structure? by fiddler42

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