英文:
How to write a test case for product sum question
问题
我正在尝试为以下代码编写一个测试用例，该代码用于查找嵌套数组的乘积和总和：
package mainimport "fmt"type SpecialArray []interface{}func ProductSum(array SpecialArray) int {return helper(array, 1)}func helper(array SpecialArray, multiplier int) int {sum := 0for _, el := range array {if cast, ok := el.(SpecialArray); ok {sum += helper(cast, multiplier + 1)} else if cast, ok := el.(int); ok {sum += cast}}return sum * multiplier}
给定一个包含整数和数组的嵌套数组，上述代码应返回所有元素的总和。嵌套数组中的元素将被求和，然后乘以它们的深度，即，
[1, [2, 3], 2] = 1 + 2(2+3) + 2 = 13
我对 SpecialArray []interface{} 类型的理解有些困惑。我最初的尝试是在我的 main 函数中简单地定义一个嵌套切片，如下所示：
func main() {SpecialArray := [][]int{1, {2, 3}, 2}result := ProductSum(SpecialArray)fmt.Println(result)}
但是这并不起作用。我猜想我需要使用值初始化我的 SpecialArray 接口，并将其传递给我的 ProductSum 函数。
英文:
I am trying to write a test case in my main function for the following code that is used to find the product and sum of a nested array:
package mainimport "fmt"type SpecialArray []interface{}func ProductSum(array SpecialArray) int {return helper(array, 1)}func helper(array SpecialArray, multiplier int) int {sum := 0for _, el := range array {if cast, ok := el.(SpecialArray); ok {sum += helper(cast, multiplier + 1)} else if cast, ok := el.(int); ok {sum += cast}}return sum * multiplier}
Given a nested array with a mix of ints and arrays, the above code should return the sum of all elements. Elements within a nested array will be summed then multiplied by their depth, i.e.,
[1, [2, 3], 2] = 1 + 2(2+3) + 2 = 13
I am having trouble understanding the SpecialArray []interface{} type. My first attempt was to simply define a nested slice in my main function as follows:
func main() {SpecialArray := [][]int{1, {2, 3}, 2}result := ProductSum(SpecialArray)fmt.Println(result)}
But this is not working. I'm assuming I need to initalize my SpecialArray interface with values and pass that to my ProductSum function.
答案1
得分: 2
你非常接近了，但是数组字面量的语法还不太正确：
func main() {special := SpecialArray{1, SpecialArray{2, 3}, 2}result := ProductSum(special)fmt.Println(result)}
另外，你的 helper 函数是正确的，但是你可以考虑使用类型切换（type switch）：
func helper(array SpecialArray, multiplier int) int {sum := 0for _, v := range array {switch v := v.(type) {case int:sum += vcase SpecialArray:sum += helper(v, multiplier+1)default:log.Fatalf("未知类型：%T", v)}}return sum * multiplier}
顺便说一下，SpecialArray 类型是一个切片（slice），而不是数组。
英文:
You are very close but did not quite get the array literal syntax right:
func main() {special := SpecialArray{1, SpecialArray{2, 3}, 2}result := ProductSum(special)fmt.Println(result)}
Also your helper function is fine as is but you might consider using a type switch:
func helper(array SpecialArray, multiplier int) int {sum := 0for _, v := range array {switch v := v.(type) {case int:sum += vcase SpecialArray:sum += helper(v, multiplier+1)default:log.Fatalf("Unknown type: %T", v)}}return sum * multiplier}
BTW the SpecialArray type is a slice not an array.
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