Leetcode 589 590: N

Leetcode 589 590: N"/>

Leetcode 589 590: N

问题描述：
多叉树的前序/后序遍历

//preorder
class Solution {public List<Integer> preorder(Node root) {List<Integer> list= new ArrayList<>();helper(root, list);return list;}private void helper(Node root, List<Integer> list){if(root==null)  return;list.add(root.val);for(Node node: root.children){helper(node, list);}return;}
}

//postOrder
class Solution {public List<Integer> postorder(Node root) {List<Integer> list=new ArrayList<>();helper(root, list);return list;}private void helper(Node root, List<Integer> list){if(root==null)  return;for(Node node: root.children){helper(node, list);}list.add(root.val);}
}