/in/foo.cc: In function 'int main()':
/in/foo.cc:28:43: warning: operation on 'tot' may be undefined [-Wsequence-point]
  if (q[0]==1) if (tot>1) q[tot]++; else q[++tot]=q[tot-1],q[1]=1;
                                           ^~~~~
/in/foo.cc:28:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
  if (q[0]==1) if (tot>1) q[tot]++; else q[++tot]=q[tot-1],q[1]=1;
     ^