MATLAB: Finding the lowest common ancestor between 2 cells array

common ancestor

Hi, I have a code that can find the lowest common ancestor ( lowest common character) and the common chaarcters for 2 vectors, the code is:
cc= ['a0.c2.b2.d6'] ;
pc= ['a0.c1.c3.d5'];
for i=1:min(length(pc),length(cc))
    if cc(i)==pc(i)
        q(i)=cc(i);
      else
         break   
      end
end
if strcmp(q,pc) | strcmp(q,cc)
       LCA=q;
else
disp('There is no LCA')
end
The problem of this code is that it takes the common character even if they are not has the same supnumber, like for eaxmple, the previous cc and pc , the answer will be :
There is no LCA
q =
a0.c
 note that it takes c as common between c2 and c1 which is not accepted. also it takes the 'dot' between character such as :
    cc= ['a0.c4.b2.d6'] ;
    pc= ['a0.c4.c3.d5'];
    for i=1:min(length(pc),length(cc))
        if cc(i)==pc(i)
            q(i)=cc(i);
        else
           break   
        end
    end
    if strcmp(q,pc) | strcmp(q,cc)
           LCA=q;
    else
    disp('There is no LCA')
    end
  q
the answer will be:
There is no LCA
q =
a0.c4.
advice me please

Best Answer

p1 = regexp(pc,'\.','split');
c1 = regexp(cc,'\.','split');
ii = ismember(p1,c1);
k = p1(1:find(ii == 0,1,'first')-1);
t = reshape([k;repmat({'.'},1,numel(k))],1,[]);
q = char(strcat(t{1:end-1}));
or
i1 = [0 strfind(pc,'.') numel(pc)+1];
i2 = [0 strfind(cc,'.') numel(cc)+1];
q = [];
for jj = 1:numel(i1)-1
    k = pc(i1(jj)+1:i1(jj+1)-1);
    if strcmp(k,cc(i2(jj)+1:i2(jj+1)-1))
        q = [q k '.'];
    else
        break
    end
end
q = q(1:end-1);
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