🟢 剑指 Offer II 052. 展平二叉搜索树

LeetCode 提示

题目难度 简单

原题链接 🔗 leetcode

题解1

/** * 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 {    private TreeNode theRoot;    private TreeNode cur;
    private void join(TreeNode node) {        if (this.cur == null) {            this.theRoot = node;            this.cur = this.theRoot;        } else {            this.cur.right = node;            this.cur = this.cur.right;        }    }
    private void visit(TreeNode node) {        if (node.left != null) {            TreeNode left  = node.left;            node.left = null;            visit(left);        }        join(node);        if (node.right != null) {            TreeNode right = node.right;            node.right = null;            visit(right);        }    }
    public TreeNode increasingBST(TreeNode root) {        this.theRoot = null;        this.cur = null;
        visit(root);        return this.theRoot;    }}