树的子结构

输入2棵二叉树A和B，判断B是不是A的子结构。

struct BinaryTreeNode //节点
{
    int m_nValue;
    BinaryTreeNode* m_pLeft;
    BinaryTreeNode* m_pRight;
};

bool DoseTree1HaveTree2(BinaryTreeNode* pRoot1 ,BinaryTreeNode* pRoot2)
{
    
    if (pRoot2 == NULL)
    {
        return true ;
    }
    if (pRoot1 == NULL)
    {
        return false ;
    }
    if (pRoot1->m_nValue != pRoot2->m_nValue)
    {
        return false ;
    }

    return DoseTree1HaveTree2(pRoot1->m_pLeft , pRoot2->m_pLeft) && DoseTree1HaveTree2(pRoot1->m_pRight ,pRoot2->m_pRight) ;
}
bool HasSubtree(BinaryTreeNode* pRoot1 ,BinaryTreeNode* pRoot2)
{
    bool result = false ;
    if (pRoot1 && pRoot2)
    {
        if (pRoot1->m_nValue == pRoot2->m_nValue)
        {
            result = DoseTree1HaveTree2(pRoot1 , pRoot2);
        }
        if (!result)
        {
            result = HasSubtree(pRoot1->m_pLeft , pRoot2);
        }
        if (!result)
        {
            result = HasSubtree(pRoot1->m_pRight , pRoot2);
        }        
    }

    return result ;
}