How to Remove Duplicates in an Array in Golang

The challenge

Remove the left-most duplicates from a list of integers and return the result.

// Remove the 3's at indices 0 and 3 // followed by removing a 4 at index 1 solve([3, 4, 4, 3, 6, 3]); // => [4, 6, 3]
Code language: Go (go)

The solution in Golang

Option 1:

package solution func Solve(arr []int) (res []int) { visited := map[int]bool{} for i := len(arr) - 1; i >= 0; i-- { n := arr[i] if visited[n] { continue } visited[n] = true res = append([]int{n}, res...) } return }
Code language: Go (go)

Option 2:

package solution func Solve(arr []int) []int { counts := make(map[int]bool) for _,x := range arr { counts[x]=true } result := make([]int,len(counts)) j := len(result)-1 for i := len(arr)-1; i>=0; i-- { if counts[arr[i]] { counts[arr[i]] = false; result[j] = arr[i] j-- } } return result }
Code language: Go (go)

Option 3:

package solution func Solve(a []int) (r[]int) { m:=map[int]int{} for _,v:=range a{ m[v]++ } for _,v:=range a{ if m[v]==1{ r=append(r,v) } m[v]-- } return }
Code language: Go (go)

Test cases to validate our solution

package our_test import ( . "github.com/onsi/ginkgo" . "github.com/onsi/gomega" . "codewarrior/kata" ) func dotest(arr , exp []int) { var ans = Solve(arr) Expect(ans).To(Equal(exp)) } var _ = Describe("Example tests", func() { It("It should work for basic tests", func() { dotest([] int{3,4,4,3,6,3}, []int{4,6,3}) dotest([] int{1,2,1,2,1,2,3}, []int{1,2,3}) dotest([] int{1,2,3,4}, []int{1,2,3,4}) dotest([] int{1,1,4,5,1,2,1}, []int{4,5,2,1}) dotest([] int{1,2,1,2,1,1,3}, []int{2,1,3}) dotest([] int{0,4,4,3,0,3}, []int{4,0,3}) }) })
Code language: Go (go)
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