题解 | #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 isSymmetrical(TreeNode* pRoot) {
        return isSymmetrical(pRoot, pRoot);
    }

    bool isSymmetrical(TreeNode* pRoot1, TreeNode* pRoot2) {
        if (pRoot1 == nullptr && pRoot2 == nullptr) return true;
        if (pRoot1 == nullptr || pRoot2 == nullptr) return false;
        if (pRoot1->val != pRoot2->val) return false;

        return isSymmetrical(pRoot1->left, pRoot2->right) && isSymmetrical(pRoot1->right, pRoot2->left);
    }

};