剑指offer（54）-二叉树的下一个结点

题目描述

代码

using namespace std;
/*
struct TreeLinkNode {
int val;
struct TreeLinkNode *left;
struct TreeLinkNode *right;
struct TreeLinkNode *next;
TreeLinkNode(int x) :val(x), left(NULL), right(NULL), next(NULL) {

}
};
*/
class Solution {
public:
TreeLinkNode* GetNext(TreeLinkNode* pNode)
{
if (pNode == NULL) {
return NULL;
}
TreeLinkNode* pNext = NULL;
if (pNode->right != NULL) {
TreeLinkNode* pRight = pNode->right;
//有又子树
while (pRight->left != NULL) {
//一直寻找这个又子树的左结点
pRight = pRight->left;
}
pNext = pRight;
}else if (pNode->next != NULL){

TreeLinkNode* pCurrent = pNode;
TreeLinkNode* pParent = pNode->next;
while (pParent != NULL && pCurrent == pParent->right) {
pCurrent = pParent;
pParent = pParent->next;
}
pNext = pParent;
}
return pNext;

}
};