The cost of building @choices (your @rndselect) is a one-off up front cost. And hardly onorous at that unless you have thousand or millions of choices.

And impossible to do well if your weights are sqrt(2), sqrt(5) and sqrt(11).

[Knuth vs BrowserUK] So O(N(/2)) compared to O(1).

Not quite a fair comparison, is it? You give yourself a preprocessing complexity of Ω(R) (in both time and memory), where R is the sum of all weights (and could hence be much larger than N), while you don't give Knuth any.

In reply to Re^4: Weighted random selection by JavaFan
in thread Weighted random selection by cosmicperl

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