紫书:P150 uva122 Background Trees are fundamental in many branches of computer science. Current state-of-the art parallel computers such as Thinking Machines' CM-5 are based on fat trees. Quad- and octal-trees are fundamental to many algorithms in comp
前序遍历 public List<Integer> preorderTraversal(TreeNode root) { ArrayList<Integer> list = new ArrayList<Integer>(); Stack<TreeNode> stack=new Stack<TreeNode>(); TreeNode p=root; while(!stack.isEmpty()||p!=null){ if(p!=null){ sta