matlab - count equal adjacent element of array -

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• run length encoding in matlab 4 answers

i've vector

a = [0;1;1;1;0;0;1;1;1;2;2;2;2]; 

and want count number of equal adjacent values in order have matrix this:

b=[0 1    1 3    0 2    1 3    2 4]; 

can me?

here short solution:

j=find(diff([a(1)-1; a])); b=[a(j), diff([j; numel(a)+1])];