/in/foo.cc:43:16: error: ISO C++ forbids declaration of 'dfs' with no type [-fpermissive]
 dfs(int r,int p)
                ^
/in/foo.cc: In function 'int dfs(int, int)':
/in/foo.cc:59:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^