Reverse an Array

Input: arr[] = {12, 7, 9, 33}
Output arr[] = {33, 9, 7, 12}

Input: arr[] = {33, 22, 9, 3, 99}
Output: arr[] = {99, 3, 9, 22, 33}

Approach One

package main

import (
    "fmt"
)

func main() {
    arr := []int{12, 7, 9, 33} // [33 9 7 12]
    // arr := []int{33, 22, 9, 3, 99} // [99 3 9 22 33
    reserveArray(arr)
    fmt.Println(arr)

}

func reserveArray(arr []int) {
    low := 0
    high := len(arr) - 1
    for low < high {
        temp := arr[low]
        arr[low] = arr[high]
        arr[high] = temp
        low++
        high--
    }
}

Time Complexity:: θ(n)
Aux Space: θ(1)

Approach Two

package main

import (
    "fmt"
)

func main() {
    // arr := []int{12, 7, 9, 33} // [33 9 7 12]
    arr := []int{33, 22, 9, 3, 99} // [99 3 9 22 33
    reverseArray(arr)
    fmt.Println(arr)

}

func reverseArray(arr []int) {
    for i := 0; i < len(arr)/2; i++ {
        temp := arr[i]
        j := len(arr) - i - 1
        arr[i] = arr[j]
        arr[j] = temp
    }
}

Time Complexity:: θ(n)
Aux Space: θ(1)