力扣538. 把二叉搜索树转换为累加树

538. 把二叉搜索树转换为累加树 - 力扣（LeetCode）

右中左遍历

/*** Definition for a binary tree node.* public class TreeNode {*     int val;*     TreeNode left;*     TreeNode right;*     TreeNode() {}*     TreeNode(int val) { this.val = val; }*     TreeNode(int val, TreeNode left, TreeNode right) {*         this.val = val;*         this.left = left;*         this.right = right;*     }* }*/
class Solution {int num = 0;//全局变量用来记录上一次的和public TreeNode convertBST(TreeNode root) {if(root==null) return root;//递归终止条件convertBST(root.right);//右root.val = root.val + num;//中num = root.val;convertBST(root.left);//左return root;}
}