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/*** 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:vector<int> inorderTraversal(TreeNode* root) {vector<int> ans;auto dfs = [&](this auto&& self, TreeNode* x) -> void {if (!x) {return;}self(x->left);ans.emplace_back(x->val);self(x->right);};dfs(root);return ans;}
};