/in/foo.cc: In function 'void bfs1(int)':
/in/foo.cc:44:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (nxt[u] < e[u].size())
             ~~~~~~~^~~~~~~~~~~~~
/in/foo.cc: In function 'void bfs2(int)':
/in/foo.cc:70:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (nxt[u] < r[u].size())
             ~~~~~~~^~~~~~~~~~~~~