二维数组如何转化为目录树结构？

package main

import (
    "encoding/json"
    "strings"
)

var values = []string{
    "answer:aa:bb",
    "answer:aa:cc",
    "question:book1",
    "question:book1:answer",
    "question:book1:answer:name1",
    "question:book1:answer:name2",
    "timeout_1",
    "timeout_2",
}

type Node struct {
    Name  string
    Value string
    Child map[string]Node
}

func main() {
    root := make(map[string]Node)

    for _, value := range values {
        t := root
        // 根据 : 拆分字符串
        keys := strings.Split(value, ":")
        l := len(keys)
        for i := 0; i < l-1; i++ {
            k := keys[i]
            if tm, has := t[k]; has {
                // 复用并进入下一层节点
                t = tm.Child
            } else {
                // 新建并进入下一层节点
                t[k] = Node{
                    Name:  k,
                    Child: map[string]Node{},
                }
                t = t[k].Child
            }
        }
        // 为最后一个 key 时 单独处理成叶子节点
        t[value] = Node{
            Name:  keys[l-1],
            Value: value,
            Child: nil,
        }
    }
    r, _ := json.Marshal(root)
    println(string(r))
}