remove unnecessary code
remove unnecessary code

baidu/bfs,myawan/bfs-1,yvxiang/coverage_for_bfs,yvxiang/coverage_for_bfs,myawan/bfs-1,yvxiang/dfs,00k/ToyDFS,lylei/dfs,imotai/bfs,imotai/bfs,myawan/bfs-1,yvxiang/dfs,imotai/bfs,yvxiang/dfs,yvxiang/coverage_for_bfs,bluebore/dfs,00k/ToyDFS,linyvxiang/dfs,lylei/dfs,bluebore/dfs,lylei/dfs,lylei/dfs,yvxiang/dfs,baidu/bfs,baidu/bfs,bluebore/bfs,bluebore/bfs,linyvxiang/dfs,baidu/bfs,bluebore/dfs,myawan/bfs-1,yvxiang/coverage_for_bfs,linyvxiang/dfs,bluebore/bfs