对称的二叉树

/*
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
*/
class Solution {
public:
    bool isSame(TreeNode* pRoot1,TreeNode* pRoot2)
    {
        if(pRoot1==NULL&&pRoot2==NULL)
        {
            return true;
        }
        if(pRoot1==NULL||pRoot2==NULL)
        {
            return false;
        }
        if(pRoot1->val!=pRoot2->val)
        {
            return false;
        }
        return isSame(pRoot1->left,pRoot2->right)&&isSame(pRoot2->left,pRoot1->right);
    }
    bool isSymmetrical(TreeNode* pRoot)
    {
        return isSame(pRoot,pRoot);
    }
};