Go function that returns the subsets of a slice.

subsets.go

func subsets[T any](v []T) [][]T {
	switch len(v) {
	case 0:
		return [][]T{
			{},
		}
	case 1:
		return [][]T{
			{v[0]},
			{},
		}
	}
	result := make([][]T, 0, power(2, len(v)))
	sub := subsets(v[1:])
	for _, s := range sub {
		result = append(result, append([]T{v[0]}, s...))
	}
	result = append(result, sub...)
	return result
}

func power(x, y int) int {
	switch y {
	case 0:
		return 1
	case 1:
		return x
	}
	for i := 2; i <= y; i++ {
		x *= x
	}
	return x
}