C# N叉數的遍歷

結點：

// Definition for a Node.
public class Node {
    public int val;
    public IList<Node> children;
    public Node(){}
    public Node(int _val,IList<Node> _children) {
        val = _val;
        children = _children;
}

前序遍歷：

public class Solution {
    public IList<int>
 
 Preorder(Node root) {
        IList<int> res = new List<int>();
        if(root == null)    return res;
        res.Add(root.val);
        for(int i = 0; i < root.children.Count; i++){
            IList<int> temp = Preorder(root.children[i]);
            if(temp != null){
                foreach
 
(var item in temp){
                    res.Add(item);
                }
            }
        }
        return res;
    }
}

後序遍歷

public class Solution {
    public IList<int> Preorder(Node root) {
        IList<int> res = new List<int>();
        if(root == null)   return res;
        for
 
(int i = 0; i < root.children.Count; i++){
            IList<int> temp = Preorder(root.children[i]);
            if(temp != null){
                foreach(var item in temp){
                    res.Add(item);
                }
            }
        }
        res.Add(root.val);
        return res;
    }
}