/in/foo.cc: In function 'int main()':
/in/foo.cc:14:33: warning: operation on 'x' may be undefined [-Wsequence-point]
  for(int i=1,x,y;i<=n;i++) ran[x=sa[i]]=s[x]>s[y=sa[i-1]]?i:ran[y];
                                ~^~~~~~