/in/foo.cc: In function 'int main()':
/in/foo.cc:50:14: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  DFS(x, y, 0);
              ^
/in/foo.cc:50:14: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]