NC16 对称的二叉树

给定一棵二叉树，判断其是否是自身的镜像（即：是否对称）

struct TreeNode {
	int val;
	struct TreeNode *left;
	struct TreeNode *right;
	TreeNode(int x) :val(x), left(nullptr), right(nullptr) {}
};

class Solution {
public:
	bool issame(TreeNode* p, TreeNode* q)
	{
		if (p == nullptr&&q == nullptr)
			return true;

		if (p == nullptr || q == nullptr)
			return false;

		return p->val == q->val&&issame(p->left, q->right) && issame(p->right, q->left);
	}

	bool isSymmetrical(TreeNode* pRoot)
	{
		if (pRoot == nullptr)
			return true;
		return issame(pRoot->left, pRoot->right);

	}
};