Tags: tree dfs tree-traversal
145. Binary Tree Postorder Traversal
Recursive
class Solution {
public:
vector<int> ans;
void postOrder(TreeNode* root) {
if (root == nullptr) return;
postOrder(root -> left);
postOrder(root -> right);
ans.push_back(root -> val);
}
vector<int> postorderTraversal(TreeNode* root) {
postOrder(root);
return ans;
}
};