woshixiaodashen的博客

You are given an array x of n positive numbers. You start at point (0,0) and moves x[0] metres to the north, then x[1] metres to the west, x[2] metres to the south,x[3] metres to the east and so

定义二叉树节点class TreeNode{ int val; TreeNode left; TreeNode right; public TreeNode(int val){ this.val = val; } }1. 前序遍历 递归 非常简单，代码如下： public void preTraversal(TreeNode root){