/in/foo.cc: In function 'int main()':
/in/foo.cc:67:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(First[head]==g[head].size())head=Link[head]; //找块表的头元素 
         ~~~~~~~~~~~^~~~~~~~~~~~~~~~
/in/foo.cc:71:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(p!=0 && First[p]==g[p].size())p=Link[p]; //找到每输出完的块 
                  ~~~~~~~~^~~~~~~~~~~~~
/in/foo.cc:77:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j=First[p];j<g[p].size();j++)
                        ~^~~~~~~~~~~~
/in/foo.cc:55:16: warning: unused variable 'id' [-Wunused-variable]
  int num=0,p,q,id;
                ^~