/in/foo.cc: In function 'int dfs1(int, int, int)':
/in/foo.cc:44:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int dfs2(int, int)':
/in/foo.cc:50:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^