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程式語言 - LeetCode - C++ - 101. Symmetric Tree

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題目：


解答：

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool isSymmetric(TreeNode* root) {
        auto dfs = [&](this auto&& dfs, TreeNode *p, TreeNode *q) {
            if (!p && !q) {
                return true;
            }
    
            if (!p || !q) {
                return false;
            }
    
            if (p->val != q->val) {
                return false;
            }
    
            return dfs(p->left, q->right) && dfs(p->right, q->left);
        };

        return dfs(root->left, root->right);
    }
};