Reversing a slice in Go can be accomplished with an efficient in-place algorithm that swaps elements from both ends of the slice moving toward the center. This approach modifies the original slice and uses constant extra space.
The manual swap approach uses two pointers: one starting at the beginning of the slice and one at the end. In each iteration, the elements at both pointers are swapped, then the pointers move toward the center. When the pointers meet or cross, the reversal is complete.
Starting with Go 1.21+, the standard library includes slices.Reverse() which provides a convenient built-in function for reversing slices. The manual approach shown here is valuable for understanding the underlying algorithm and works with all Go versions. Both methods modify the slice in-place, making them memory-efficient for large slices.