### Question:
NonrecursiveDFS { public static List<Integer> dfs(List<Integer>[] graph) { return null; }  static List<Integer> dfs(List<Integer>[] graph);  }### Answer:
@Test public void randomTest() { int N = 2000; for (int i = 10; i <= N; i *= 2) { List<Integer>[] graph = GraphBuilder.buildRandomUndirectGraph(i, true); Assert.assertEquals(expect(graph), NonrecursiveDFS.dfs(graph)); } }