面试题8：二叉树的下一个节点

struct BinaryTreeNode {int m_value;BinaryTreeNode* m_lchild;BinaryTreeNode* m_rchild;BinaryTreeNode* m_father;};BinaryTreeNode* GetNext(BinaryTreeNode* pNode){if (pNode == nullptr) return nullptr;BinaryTreeNode* pNext = nullptr;if (pNode->m_rchild != nullptr) {BinaryTreeNode* pRight = pNode->m_rchild;while (pRight->m_lchild) {pRight = pRight->m_lchild;}pNext = pRight;}else if (pNode->m_father != nullptr) {BinaryTreeNode* pCurrent = pNode;BinaryTreeNode* pParent = pNode->m_father;while (pParent && pCurrent == pParent->m_rchild) {pCurrent = pParent;pParent = pParent->m_father;}pNext = pParent;}return pNext;}