Determining the order of a list of numbers (possibly without sorting)
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by Victor Liu
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Published on 2010-05-05T23:07:09Z
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2010/05/05
23:28 UTC
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I have an array of unique integers (e.g. val[i]
), in arbitrary order, and I would like to populate another array (ord[i]
) with the the sorted indexes of the integers. In other words, val[ord[i]]
is in sorted order for increasing i
.
Right now, I just fill in ord
with 0, ..., N, then sort it based on the value array, but I am wondering if we can be more efficient about it since ord
is not populated to begin with. This is more of a question out of curiousity; I don't really care about the extra overhead from having to prepopulate a list and then sort it (it's small, I use insertion sort). This may be a silly question with an obvious answer, but I couldn't find anything online.
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