Given an n-ary tree, return the postorder traversal of its nodes' values.
For example, given a 3-ary
tree:
Return its postorder traversal as: [5,6,3,2,4,1]
.
解题思路一:递归实现。
/*
// Definition for a Node.
class Node {
public int val;
public List<Node> children;
public Node() {}
public Node(int _val,List<Node> _children) {
val = _val;
children = _children;
}
};
*/
class Solution {
public List<Integer> postorder(Node root) {
List<Integer> res = new ArrayList<>();
postOrder(res,root);
return res;
}
public void postOrder(List<Integer> res, Node root){
if(root == null) return;
for(Node node:root.children)
postOrder(res,node);
res.add(root.val);
}
}