The problem
You may be given an integer array and your job is to return the sum of components occupying prime-numbered indices.
The primary aspect of the array is at index “.
The answer in Golang
Choice 1:
bundle answer
import "math/large"
func Clear up(arr []int) int {
c := 0
for i := 0; i < len(arr); i++ {
n := arr[i]
if large.NewInt(int64(i)).ProbablyPrime(0) {
c += n
}
}
return c
}
Choice 2:
bundle answer
func Clear up(arr []int) int {
var sieve = make([]bool, len(arr))
rely := 0
for i := 2; i < len(arr); i++ {
if !sieve[i] {
rely += arr[i]
for j := i * i; j < len(sieve); j += i {
sieve[j] = true
}
}
}
return rely
}
Choice 3:
bundle answer
func Clear up(arr []int) int {
rely := 0
sum := 0
for i := 2; i < len(arr); i++{
for c, n := i, 2; c > 0; n++{
if i % n == 0{
rely++
c /= n
n--
}
}
if rely < 3 {
sum += arr[i]
}
rely = 0
}
return sum
}
Take a look at circumstances to validate our answer
bundle solution_test
import (
. "github.com/onsi/ginkgo"
. "github.com/onsi/gomega"
)
func dotest(arr []int, exp int) {
var ans = Clear up(arr)
Anticipate(ans).To(Equal(exp))
}
var _ = Describe("Instance checks", func() {
It("It ought to work for fundamental checks", func() {
dotest([]int {}, 0)
dotest([]int {1,2,3,4},7)
dotest([]int {1,2,3,4,5,6}, 13)
dotest([]int {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15},47)
})
})
