对称二叉树#101

    1
   / 
  2   2
 /  / 
3  4 4  3

    1
   / 
  2   2
      
   3    3

//C style
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
bool checkutSymmetric(struct TreeNode* q,struct TreeNode* p) {
    if(!q && !p) return true;
    if(!q || !p) return false;
    return (q->val == p->val) && checkutSymmetric(q->left,p->right) &&checkutSymmetric(q->right,p->left);
}

bool isSymmetric(struct TreeNode* root) {
    if(!root) return true;
    
    return checkutSymmetric(root->left,root->right);
}

[1,2,2,3,4,4,3]

true