MATLAB: Comparing two matrix element simultaneously and adding third column

comparinglogical?MATLABmatrix

the problem is extension of the question https://www.mathworks.com/matlabcentral/answers/106095-comparing-matrix-elements-and-performing-operation-if-equal
whenever the elemnts in column 1 and 3 both are repeated elsewhere in matrix then only third column should get added up
e.g
A=
18 18 1
17 20 2
18 18 1
17 25 2
19 17 3
18 18 1
19 17 3
then answer should be
18 18 1
17 20 2
18 18 2
17 25 2
19 17 3
18 18 3
19 17 6

Best Answer

A = [ 18   18    1
   17   20    2
   18   18    1
   17   25    2
   19   17    3
   18   18    1
   19   17    3] ;
[c,ia,ib] = unique(A(:,1:2),'rows') ; 
B = A ; 
% [c,ia,ib] = unique(A(:,3)) ; 
for i = 1:length(c)
    B(ib==i,3) = cumsum(A(ib==i,3)) ;
end
B
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