Method isSymmetric

101. Symmetric Tree/Solution.cpp:26–29

class Solution {
public:
    bool isSymmetric(TreeNode* root) {
        if (root == NULL) return true;
        else return isSymmetric(root->left, root->right);
    }

    bool isSymmetric(TreeNode * left, TreeNode * right) {
        if (left == NULL and right == NULL) return true;