// leetcode problem - https://leetcode.com/problems/binary-tree-inorder-traversal/submissions/
// tc - o(N) n is no of nodes 
// sc - o(N)



/**
 * 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 {
    void dfs(TreeNode *node, vector<int> &inorder){
        if(node == NULL)
            return;
        
        dfs(node->left, inorder);
        inorder.push_back(node->val);
        dfs(node->right, inorder);
    }
public:
    vector<int> inorderTraversal(TreeNode* root) {
        
        vector<int> inorder;
        dfs(root, inorder);
        return inorder;
        
    }
};
