function P=randTree(n)
  E=[];
  L=[1];
  for i=1:n/2
    k=randi(length(L));
    p=L(k);
    L(k)=[];
    E=[E;p,2*i];
    E=[E;p,2*i+1];
    L(end+1)=2*i;
    L(end+1)=2*i+1;
    disp(L);
  endfor

  for i=1:max(max(E)) 
    P(i).id=i; 
    P(i).ch=[]; 
    P(i).label=0; 
  endfor;

  for i= 1:rows(E)
    P(E(i,1)).ch(end+1)=E(i,2);
  endfor

endfunction