leetcode 94.二叉树的中序遍历

vector<int> ans;

void dfs(TreeNode* now){
    if (now==nullptr)
        return ;
    dfs(now->left);
    ans.push_back(now->val);
    dfs(now->right);
}

class Solution {
public:
    vector<int> inorderTraversal(TreeNode* root) {
        ans.clear();
        dfs(root);
        return ans;
    }
};