题解 | #二叉树的下一个结点#

/*
struct TreeLinkNode {
    int val;
    struct TreeLinkNode *left;
    struct TreeLinkNode *right;
    struct TreeLinkNode *next;
    TreeLinkNode(int x) :val(x), left(NULL), right(NULL), next(NULL) {
        
    }
};
*/
#include <cstddef>
class Solution {
public:
    TreeLinkNode* GetNext(TreeLinkNode* pNode) {
        if(pNode->right==NULL)
        {
            if(pNode->next==NULL)
            {
                return NULL;
            }
            TreeLinkNode *n=pNode;
            pNode=pNode->next;
            while(pNode->right==n)
            {
                n=pNode;
                if(pNode->next==NULL)
                {
                    return NULL;
                }
                pNode=pNode->next;
            }
            return pNode;
        }
        else 
        {
            pNode=pNode->right;
            while(pNode->left!=NULL)
            {
                pNode=pNode->left;
            }
            return pNode;
        }
    }
};