How to check if a sequence of numbers has a increasing/decreasing trend in C++

c++ vector int trend
INElutTabile picture INElutTabile · Dec 2, 2013 · Viewed 16.1k times · Source

What's the best way to check if a sequence of numbers has an increasing or decreasing trend?

I know that I could pick the first and last value of the sequence, and check their difference, but I'd like a somewhat more robust check. This means that I want to be able to tolerate a minority of increasing values within a mostly decreasing sequence, and viceversa.

More specifically, the numbers are stored as

vector<int> mySequence;

A few more details about the number sequences that I am dealing with:

  • All the numbers within the sequence have the same order of magnitude. This means that no sequence like the following can appear: [45 38 320 22 12 6].
  • By descending trend I mean that most or all the numbers within the sequence are lesser than the previous one. (The opposite applies for ascending trend). As a consequence, the following sequence is to be considered as descending: [45 42 38 32 28 34 26 20 12 8 48]

Answer

Kristian D&#39;Amato picture Kristian D'Amato · Dec 2, 2013

I would accumulate the number of increases vs number of decreases, which should give you an idea of whether there's an overall trend to increase or decrease.

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