Cacher is the code snippet organizer for pro developers

//Runtime: 0 ms, faster than 100.00%

#include <ios>
static auto fastInput = []() {
    ios_base::sync_with_stdio(false),cin.tie(nullptr);
    return 0;
}();

class Solution {
public:
    vector<int> array;
    
    vector<int> postorderTraversal(TreeNode* root) {
        travelTree(root);
        return array;
    }
    
    void travelTree(TreeNode* root){
        if(root){
            travelTree(root->left);
            travelTree(root->right);
            array.push_back(root->val);
        }
    }
};