二叉搜索树与双向链表

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

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

    }

}
*/
public class Solution {
    public TreeNode Convert(TreeNode pRootOfTree) {
        if(pRootOfTree==null){
            return null;
        }
        if(pRootOfTree.left==null&&pRootOfTree.right==null){
            return pRootOfTree;
        }
        TreeNode left=Convert(pRootOfTree.left);
        TreeNode p=left;
        if(p!=null){
            while(p.right!=null){
                p=p.right;
        }
            p.right=pRootOfTree;
            pRootOfTree.left=p;
        }

        TreeNode right=Convert(pRootOfTree.right);
        if(right!=null){
            right.left=pRootOfTree;
            pRootOfTree.right=right;
        }
        
        return left==null?pRootOfTree:left;
    }

    
}