Arrange be in order of their pairing, and count how many times they appear

I have 2 matices, A and B. What I want to do is for B to be rearranged like C, and remove any repreated row.

A = [1; 2; 3; 4; 5; 6;];
B = [1 2; 2 3; 1 2; 1 3; 1 4; 1 2;]

I would like to produce C with A and B

C = [1 2;
    1 3;
    1 4;
    2 3;]

Thereafter, after reordering them, I want to add the same pair i.e. add all the 1 2s together like in D.

D = [1+3+6;
     4;
     5;
     2;];

  = [9;
     4;
     5;
     2;];

Answer 1

[the cyclist]

[C,~,idx] = unique(B,'row');
D = accumarray(idx,A);

1 + 3 + 6 = 10. ;-)

[dpb]

My interpretation is that D should be

>> accumarray(ix,sum(B,2))
ans =
     9
     4
     5
     5
>> 

but the description is confusing at best and the answer presented isn't correct whichever is the actual definition wanted...

[JL]

thanks guys!