Reverse the array

Reverse an Array

Reversing an array means rearranging the elements such that the first element becomes the last, the second element becomes the second last, and so on.

Problem Statement

Given an array, reverse its elements.

Example 1

Input
arr = [1, 4, 3, 2, 6, 5]

Output
[5, 6, 2, 3, 4, 1]

Example 2

Input
arr = [4, 5, 1, 2]

Output
[2, 1, 5, 4]

Approach 1 Using Two Pointers

In this method, we swap elements from the beginning and end moving towards the center.

Steps

Start one pointer at the beginning
Start another pointer at the end
Swap both elements
Move the first pointer forward
Move the second pointer backward
Continue until both pointers meet

Code

```python id="rev1"
def reverseArray(arr):
left = 0
right = len(arr) - 1

while left < right:
    arr[left], arr[right] = arr[right], arr[left]
    left += 1
    right -= 1

return arr




---

## Approach 2 Using Built in Method

Python provides a simple way to reverse an array.



```python id="rev2"
def reverseArray(arr):
    return arr[::-1]

Approach 3 Using Reverse Function

```python id="rev3"
def reverseArray(arr):
arr.reverse()
return arr




---

## Explanation

Reversing works by swapping elements from opposite ends. The first element goes to the last position, the second to the second last, and this continues until the middle is reached.

---

## Conclusion

Reversing an array is a basic problem that helps in understanding indexing and element swapping. It is commonly used in many algorithms and coding interviews.

Practice different methods to become comfortable with array manipulation.

Forem