/in/foo.cc: In function 'void dfs1(int, int)':
/in/foo.cc:19:7: warning: variable 'hahaha' set but not used [-Wunused-but-set-variable]
   int hahaha[10000005];
       ^
/in/foo.cc: In function 'void dfs2(int, int)':
/in/foo.cc:33:7: warning: unused variable 'v2' [-Wunused-variable]
   int v2;
       ^