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
*/
var (
	pre *TreeNode
	cur *TreeNode
)
func Convert(pRootOfTree *TreeNode) *TreeNode {
	// write code here
	if pRootOfTree == nil {
		return nil
	}
	
	Convert(pRootOfTree.Left)
	
	if pre == nil {
		pre = pRootOfTree
		cur = pRootOfTree
	} else {
		pre.Right = pRootOfTree
		pRootOfTree.Left = pre
		pre = pRootOfTree
	}
	
	Convert(pRootOfTree.Right)
	
	return cur
}