/in/foo.cc: In function 'int bfs_1(int, int, int*, int*)':
/in/foo.cc:59:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i=0;i<cw[now].size();i++)
                      ~^~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:99:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i=0;i<cw.size();i++)
                      ~^~~~~~~~~~