【leetcode 简单】第二十二题 对称二叉树

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */

bool Symmetric(struct TreeNode *left,struct TreeNode *right);
bool isSymmetric(struct TreeNode* root) {
    if(!root)
    {
        return true;
    }
    return Symmetric(root->left,root->right);    
}
bool Symmetric(struct TreeNode *left,struct TreeNode *right)
{
    
    if (left == NULL && right == NULL)
    {
        return true;
    }
    if (left == NULL  ||  right == NULL)
    {
        return false;
    }
    if ( left->val != right->val)
    {
        return false;
    }
    
    return Symmetric(left->left,right->right) && Symmetric(left->right,right->left);

}