1000311. 递增顺序搜索树

难度: Easy

题目描述

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解题思路

代码实现

解决方案

java

/**
 * 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 {
    TreeNode d;

    public TreeNode increasingBST(TreeNode root) {
        TreeNode dummyNode = new TreeNode(-1);
        d = dummyNode;
        TreeNode res = d;
        midOrder(root);
        return dummyNode.right;

    }

    private void midOrder(TreeNode root) {
        if (root == null) {
            return;
        }
        midOrder(root.left);
        d.right = root;
        root.left = null;
        d = root;
        midOrder(root.right);
    }
}