Comparing two matrix elements summing third and storing them separately

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

After that i want that the final matriz should be of the form

x = [ 17 20 2

17 25 2

18 18 3

19 17 6]

Answer 1

[madhan ravi]

T = array2table(A);
t = groupsummary(T,{'A1','A2'},'sum');
x = t{:,[1,2,end]}

[madhan ravi]

Or:

[u,~,idx] = unique(A(:,1:2),'rows');
x = [u,accumarray(idx,A(:,3),[],@sum)]

Answer 2

[Andrei Bobrov]

[B,BB] = groupsummary(A(:,3),A(:,1:2),'sum');
out = [BB{:},B];