All the Ways to Divide an Array in Two in Golang

The challenge

Write a function partlist that gives all the ways to divide an array of at least two elements into two non-empty parts.

  • Each two non empty parts will be in a pair
  • Each part will be in a string
  • Elements of a pair must be in the same order as in the original array.

Examples:

a = ["az", "toto", "picaro", "zone", "kiwi"] --> [("az", "toto picaro zone kiwi"), ("az toto", "picaro zone kiwi"), ("az toto picaro", "zone kiwi"), ("az toto picaro zone", "kiwi")]
Code language: JavaScript (javascript)

The solution in Golang

Option 1:

package solution import ("strings"; "fmt") func PartList(l []string) (r string) { for i := 1; i < len(l); i++ { a := strings.Join(l[0:i], " ") b := strings.Join(l[i:], " ") r += fmt.Sprintf("(%s, %s)", a, b) } return }
Code language: Go (go)

Option 2:

package solution import . "strings" func PartList(arr []string) string { var sb Builder n := len(arr) for x := 1; x < n; x++ { sb.WriteString("(" + Join(arr[:x], " ") + ", " + Join(arr[x:], " ") + ")") } return sb.String() }
Code language: Go (go)

Option 3:

package solution import ( "fmt" "strings" ) func PartList(arr []string) string { str := "" for i := 0 ; i < len(arr) - 1 ; i++ { str += appended(arr, i) } fmt.Println(str) return str } func appended(strs []string, index int) string { tmp := make([]string, len(strs)) copy(tmp, strs) tmp[index] += "," return fmt.Sprintf("(%s)", strings.Join(tmp, " ")) }
Code language: Go (go)

Test cases to validate our solution

package solution_test import ( . "github.com/onsi/ginkgo" . "github.com/onsi/gomega" "strings" "math/rand" "time" ) func dotest(arr []string, exp string) { var ans = PartList(arr) Expect(ans).To(Equal(exp)) } func randStringBytes(n int) string { const letterBytes = "abcde1fghij2klmno3pqrs4tuvwxyz5ABCDEF6GHIJKL7MNOPQR8STUV9WXYZ" b := make([]byte, n) for i := range b { b[i] = letterBytes[rand.Intn(len(letterBytes))] } return string(b) } func random(min, max int) int { return rand.Intn(max - min) + min } func doStringArray(n int) []string { var res []string for i := 0; i < n; i++ { res = append(res, randStringBytes(random(5, 15))) } return res } func PartListPVX(arr []string) string { res := "" for i := 1; i <= len(arr) - 1; i++ { res += "(" + strings.Join(arr[0:i], " ") + ", " + strings.Join(arr[i:len(arr)], " ") + ")" } return res } func randomtest() { rand.Seed(time.Now().UTC().UnixNano()) for i := 0; i < 100; i++ { k := random(8, 12) s := doStringArray(k) sol := PartListPVX(s) dotest(s, sol) } } var _ = Describe("Tests PartList", func() { It("should handle basic cases", func() { dotest([]string{"I", "wish", "I", "hadn't", "come"}, "(I, wish I hadn't come)(I wish, I hadn't come)(I wish I, hadn't come)(I wish I hadn't, come)") dotest([]string{"cdIw", "tzIy", "xDu", "rThG"}, "(cdIw, tzIy xDu rThG)(cdIw tzIy, xDu rThG)(cdIw tzIy xDu, rThG)") dotest([]string{"vJQ", "anj", "mQDq", "sOZ"}, "(vJQ, anj mQDq sOZ)(vJQ anj, mQDq sOZ)(vJQ anj mQDq, sOZ)") dotest([]string{"mkC", "WoiP", "pCHh", "mkv"}, "(mkC, WoiP pCHh mkv)(mkC WoiP, pCHh mkv)(mkC WoiP pCHh, mkv)") dotest([]string{"vHW", "bPq", "pme", "jJr", "HGHV"}, "(vHW, bPq pme jJr HGHV)(vHW bPq, pme jJr HGHV)(vHW bPq pme, jJr HGHV)(vHW bPq pme jJr, HGHV)") dotest([]string{"YZd", "ptUD", "IXr"}, "(YZd, ptUD IXr)(YZd ptUD, IXr)") dotest([]string{"dOXj", "nMlK", "QGT", "LSt", "BHNR"}, "(dOXj, nMlK QGT LSt BHNR)(dOXj nMlK, QGT LSt BHNR)(dOXj nMlK QGT, LSt BHNR)(dOXj nMlK QGT LSt, BHNR)") }) It("should handle random cases", func() { randomtest() }) })
Code language: Go (go)
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