【LeetCode】Symmetric Tree

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    bool isSymmetric(TreeNode *left,TreeNode *right) {if (left == NULL && right == NULL)return true;if (!left || !right)return false;return (left->val == right->val) && isSymmetric(left->left, right->right) && (isSymmetric(left->right, right->left));}bool isSymmetric(TreeNode *root) {if (root == NULL)return true;else{return isSymmetric(root->left, root->right);}}};