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145.java
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145.java
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sample 0 ms submission
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public List<Integer> postorderTraversal(TreeNode root) {
List<Integer> al = new ArrayList<Integer>();
computePostOrder(root, al);
return al;
}
private void computePostOrder(TreeNode root, List<Integer> al) {
if(root == null) return;
computePostOrder(root.left, al);
computePostOrder(root.right, al);
al.add(root.val);
return;
}
}
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sample 33408 kb submission
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public List<Integer> postorderTraversal(TreeNode root) {
List<Integer> res = new ArrayList<>();
helper(root, res);
return res;
}
public void helper(TreeNode root, List<Integer> res){
if(root == null) return;
if(root.left!=null) helper(root.left, res);
if(root.right!=null) helper(root.right, res);
res.add(root.val);
}
}
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