Remove useless code
Remove useless code

bluebore/dfs,linyvxiang/dfs,baidu/bfs,linyvxiang/dfs,lylei/dfs,yvxiang/coverage_for_bfs,bluebore/dfs,yvxiang/dfs,bluebore/dfs,linyvxiang/dfs,lylei/dfs,baidu/bfs,yvxiang/dfs,bluebore/bfs,lylei/dfs,bluebore/bfs,bluebore/bfs,yvxiang/coverage_for_bfs,myawan/bfs-1,lylei/dfs,yvxiang/coverage_for_bfs,myawan/bfs-1,baidu/bfs,myawan/bfs-1,yvxiang/dfs,yvxiang/dfs,myawan/bfs-1,baidu/bfs,yvxiang/coverage_for_bfs