Java实题演练二叉搜索树与双向链表分析

/**
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;
        }  
        TreeNode head = pRootOfTree;      
        convertChild(pRootOfTree);
        while(head.left!=null){
            head = head.left;
        }
        return head;
    }
    TreeNode prev = null;
    //pCur为当前节点
    private void convertChild(TreeNode pCur){
        //递归出口
        if(pCur == null){
            return ;
        }
        //中序遍历，先找到最左边的节点，并与prev建立连接
        convertChild(pCur.left);
        pCur.left = prev;
        if(prev != null){
            prev.right = pCur;
        }
        //prev更新
        prev = pCur;
        convertChild(pCur.right);
    }
}