How to put the values into adjacent matrix?

I have matrix A=[2,2; 4,2; 3,4; 3,1]. The first column represents x axis, the second column represents y axis of the points. So I have 4 points. And I need make adjacent matrix of x elements of points. So, A=[x1,x2,x3,x4]=>A=[2,4,3,3]

How to make adjacent matrix like this?:

Answer 1

[Geoff Hayes]

Beibit - it seems that the second column of your matrix A is ignored, so the code would just be

 A=[2,2; 4,2; 3,4; 3,1];
 adjMat = zeros(4,4);
 for u=1:4
      for v=1:4
          adjMat(v,u) = A(u,1)-A(v,1);
      end
  end