题解 | 二叉搜索树与双向链表

package main

import . "nc_tools"

/*
 * type TreeNode struct {
 *   Val int
 *   Left *TreeNode
 *   Right *TreeNode
 * }
 */

/**
 *
 * @param pRootOfTree TreeNode类
 * @return TreeNode类
 */
func Convert(root *TreeNode) *TreeNode {
	// write code here
	var pre, head *TreeNode
	var dfs func(node *TreeNode)
	dfs = func(node *TreeNode) {
		if node == nil {
			return
		}
		// 中序遍历
		dfs(node.Left)
		if pre != nil {
			pre.Right = node
		} else {
			head = node
		}
		node.Left = pre
		pre = node
		dfs(node.Right)
	}
	dfs(root)
	return head
}