small opt

n = size(a, 1);

s = {1};

D = Inf*(1:n);

P = cell(1,n);

while numel(s)

   p = s{end};

   s(end)=[];

   t = a(p(end),:);

   k = setdiff(find(t), p);

   for q = k

      r = [p q];

      s{end+1} = r;

      d = 0;

      for i = 2:nnz(r)

         d = d + norm(b(r(i),:) - b(r(i-1),:));

      end

l=r(end);
      if d < D(l)

         D(l) = d;

         P{l} = r;

      end

   end

end



D(D>9e9)=0;

[i,j]=max(D);

c=P{j}