Add ReverseCopy (#37)

README.md

@@ -63,6 +63,7 @@ Package stl4go is a generic container and algorithm library for go.
 - [func RemoveIf[T any](a []T, cond func(T) bool) []T](<#func-removeif>)
 - [func RemoveIfCopy[T any](a []T, cond func(T) bool) []T](<#func-removeifcopy>)
 - [func Reverse[T any](a []T)](<#func-reverse>)
+- [func ReverseCopy[T any](a []T) []T](<#func-reversecopy>)
 - [func Shuffle[T any](a []T)](<#func-shuffle>)
 - [func Sort[T Ordered](a []T)](<#func-sort>)
 - [func SortFunc[T any](a []T, less func(x, y T) bool)](<#func-sortfunc>)
@@ -534,6 +535,16 @@ Reverse reverses the order of the elements in the slice a.
 
 Complexity: O\(len\(a\)\).
 
+## func [ReverseCopy](<https://github.com/chen3feng/stl4go/blob/master/transform.go#L167>)
+
+```go
+func ReverseCopy[T any](a []T) []T
+```
+
+ReverseCopy returns a reversed copy of slice a.
+
+Complexity: O\(len\(a\)\).
+
 ## func [Shuffle](<https://github.com/chen3feng/stl4go/blob/master/transform.go#L149>)
 
 ```go

transform.go

@@ -160,3 +160,14 @@ func Reverse[T any](a []T) {
 		a[i], a[j] = a[j], a[i]
 	}
 }
+
+// ReverseCopy returns a reversed copy of slice a.
+//
+// Complexity: O(len(a)).
+func ReverseCopy[T any](a []T) []T {
+	b := make([]T, 0, len(a))
+	for i := len(a) - 1; i >= 0; i-- {
+		b = append(b, a[i])
+	}
+	return b
+}

transform_test.go

@@ -107,3 +107,9 @@ func Test_Reverse_Odd(t *testing.T) {
 	Reverse(a)
 	expectTrue(t, Equal(a, []int{5, 4, 3, 2, 1}))
 }
+
+func Test_ReverseCopy(t *testing.T) {
+	a := []int{1, 2, 3, 4, 5}
+	b := ReverseCopy(a)
+	expectTrue(t, Equal(b, []int{5, 4, 3, 2, 1}))
+}