448. 找到所有数组中消失的数字

package main
import "fmt"
func findDisappearedNumbers(nums []int) []int {
    r :=make([]int,len(nums))
    for _,v:=range nums {
        r[v-1] =r[v-1]+1
    }
    var res []int
    for i,v:=range r{
        if v==0 {
            res =append(res,i+1)
        }
    }
    return res
}
func main() {
    fmt.Println(findDisappearedNumbers([]int{4,3,2,7,8,2,3,1}))
}