Cyclically rotate an array by one

Problem

Given an array, rotate the array by one position in clock-wise direction.

Examples:

Example 1:

Input:
N = 5
A[] = {1, 2, 3, 4, 5}
Output:
5 1 2 3 4

Example 2:

Input:
N = 8
A[] = {9, 8, 7, 6, 4, 2, 1, 3}
Output:
3 9 8 7 6 4 2 1

Your task:

You don't need to read input or print anything. Your task is to complete the function rotate() which takes the array A[] and its size N as inputs and modify the array in place.

• Expected Time Complexity: $O(N)$
• Expected Auxiliary Space: $O(1)$

Constraints:

• $1<=N<=10^5$
• $0<=a[i]<=10^5$

Solution

Python

def rotate( arr, n):
    last_el = arr[n - 1]
    for i in range(n - 1, 0, -1):
        arr[i] = arr[i - 1]
    arr[0] = last_el

Java

public void rotate(int arr[], int n) {
    int last_el = arr[arr.length - 1], i;
    for (i = arr.length - 1; i > 0; i--)
        arr[i] = arr[i - 1];
    arr[0] = last_el;
}

C++

void rotate(int arr[], int n) {
    int last_el = arr[n - 1];
    for (int i = n - 1; i > 0; i--) {
        arr[i] = arr[i - 1];
    }
    arr[0] = last_el;
}

C

void rotate(int arr[], int n) {
    int last_el = arr[n - 1];
    for (int i = n - 1; i > 0; i--)
        arr[i] = arr[i - 1];
    arr[0] = last_el;
}

• Time Complexity: $O(N)$
• Auxiliary Space: $O(1)$