LeetCode-Solutions-in-Cpp17

Solutions to high-frequency interview questions of LeetCode in C++17, taking into account both efficiency and comprehensibility.

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• 检查左右子树是否镜像即可

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

  bool dfs(TreeNode* l, TreeNode* r) {
    if (!l && !r) {
      return true;
    }
    if (!l || !r) {
      return false;
    }
    if (l->val != r->val) {
      return false;
    }
    return dfs(l->left, r->right) && dfs(l->right, r->left);
  }
};