树中两个结点的最低公共祖先

struct TreeNode
{
	int val;
	TreeNode* left;
	TreeNode* right;
	TreeNode* m_vChildren;
};

TreeNode* GetLastCommonParent(TreeNode* pRoot, TreeNode* pNode1, TreeNode* pNode2)
{
	if (pRoot == nullptr || pNode1 == nullptr || pNode2 == nullptr)
		return nullptr;

	list path1;
	GetNodePath(pRoot, pNode1, path1);

	list path2;
	GetNodePath(pRoot, pNode2, path2);

	return GetLastCommonNode(path1, path2);
}
bool GetNodePath(TreeNode* pRoot, TreeNode* pNode, list& path)
{
	if (pRoot == pNode)
		return true;

	bool found = false;
	vector::iterator iter = pRoot->m_vChildren.begin();
	path.push_back(pRoot);
	while (!found&&iter < pRoot->m_vChildren.end())
	{
		found = GetNodePath(*iter, pNode, path);
		++iter;
	}
	if (!found)
		path.pop_back();
	return found;
}
TreeNode* GetLastCommonNode(const list& path1, const list& path2)
{
	list::const_iterator iterator1 = path1.begin();
	list::const_iterator iterator2 = path2.begin();
	TreeNode* pLast = nullptr;
	while (iterator1 != path1.end() && iterator2 != path2.end())
	{
		if (*iterator1 == *iterator2)
			pLast = *iterator1;
		++iterator1;
		++iterator2;
	}
	return pLast;
}