589. N叉树的前序遍历

589. N叉树的前序遍历

package main
type Node struct {
    Val      int
    Children []*Node
}
func preorder(root *Node) []int {
    if root==nil{
        return nil
    }
    res :=make([]int,0)
    helper(root,&res)
    return res
}
func helper(root *Node,res *[]int){
    if root==nil{
        return
    }
    *res = append(*res,root.Val)
    for i:=0;i<len(root.Children);i++{
        helper(root.Children[i],res)
    }
}
func main() {
}