题解 | #二叉搜索树与双向链表#

中序遍历直接搞定

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
import java.util.*;
public class Solution {
    public TreeNode Convert(TreeNode pRootOfTree) {
        Stack<TreeNode>  stack = new Stack<>();
        List<Integer> list = new ArrayList<>();
        TreeNode node = new TreeNode(0);
        TreeNode res = node;
        //stack.add(pRootOfTree);
        int count=0;
        while(stack.empty()==false||pRootOfTree!=null){
             while(pRootOfTree!=null){
                 stack.push(pRootOfTree);
                 pRootOfTree = pRootOfTree.left;
             }
             TreeNode temp =stack.pop();
             node.right=new TreeNode(temp.val);
             if(count>0)node.right.left=node;
             node = node.right;
             pRootOfTree = temp.right;
             count++;
        }
        
        return res.right;
    }
}