Finding pairs and finding the value of m variable

Asked Oct 12 '20 at 16:22

Active Oct 12 '20 at 17:06

Viewed 49 times

If a [i] is equal for m pieces different i, how do we get the number of equal pairs it gives rise to? (If m <2 there will be no pairs at all, if m = 2 there will be one pair, if m = 3 there will be three pairs, if m = 4 there will be the six pairs,… What will it be in general?)

int [] a = { 1, 2, 3, 1, 3, 1 };

I have used the following method but it doesn't give me full answer when it comes to figuring out the answer for m?

int pairs = 0;
int m = 0; 
N = array.length
       for (int i = 0; i < N; i++) { 
          for (int j = i+1; j < N; j++) { 
            if (array[i] == array[j])  
                    pairs++; 
           }
       return pairs;
        }

It gives 3 as an output for pairs but an explanation of how to find out m will be appreciated!

Thanks in advance

edited Oct 12 '20 at 16:58

asked Oct 12 '20 at 16:22

Demo

What answer does it give you and do you understand why? – Thorbjørn Ravn Andersen Oct 12 '20 at 16:24
Thanks for the approach! It gives me 3 as an output, yes because Im only looking for pairs but can not really understand the concept of using m? I mean the overall concept of the question? – Demo Oct 12 '20 at 16:26
You should check out "stackoverflow.com/help" for help on how and what to ask. https://stackoverflow.com/help – cliff2310 Oct 12 '20 at 16:30
I have already checked that before asking for help! Did enough approaches myself but didn't upload all the unnecessary stuff. Btw thanks for ur comment! – Demo Oct 12 '20 at 16:48
Does this help? https://stackoverflow.com/questions/2201113/combinatoric-n-choose-r-in-java-math – Abra Oct 12 '20 at 17:14
Start with a much smaller list - 2-3 entries - and see if you get what you expect. – Thorbjørn Ravn Andersen Oct 12 '20 at 17:52
Not depended on the number of entries in the list. – Demo Oct 14 '20 at 10:23

Finding pairs and finding the value of m variable

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