剑指offer-中序遍历的下一个结点

题目：

求二叉树中序遍历的下一个结点。

根据二叉树中序遍历的特点，中序遍历是从小到大排序的，以左根右顺序依次遍历二叉树。

/找出中序遍历的下一个结点struct BinaryTree{int data;BinaryTree *left;BinaryTree *right;BinaryTree *parent;};BinaryTree *GetNext(BinaryTree *pNode){if (pNode == NULL)return NULL;BinaryTree *pNext = NULL;if (pNode->right != NULL){BinaryTree *pRight = pNode->right;while (pRight->left != NULL)pRight = pRight->left;pNext = pRight;}else if (pNode->parent != NULL){BinaryTree *temp = pNode;BinaryTree *pParent = pNode->parent;while (pNode->parent != NULL&&pNode == pNode->parent->right){temp = pParent;pParent = pParent->parent;}pNext = pParent;}return pNext;}