101. 对称二叉树c

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

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

结果：