摘要：public class Singleton { private static Singleton singleton; private static readonly object obj = new object(); private Singleton() { } public static 阅读全文

摘要：如果不是用递归，可以通过压栈来完成 public static void PreOrderNoRecursion(Tree tree) { if (tree == null) return; System.Collections.Generic.Stack<Tree> stack = new Sys 阅读全文