To rotate an array left to right or right to left we can follow any of these two approach

• Using an temporary array with size of the rotation value

• By rotating item by item, without using any temporary array

By Rotating item by item

Let's consider an array and rotation value (d) =2

int num[] = {3,4,5,6,7,8,9,1,2};

After the rotation of the array will be

num[] = {5,6,7,8,9,1,2,3,4};

Instead of taking any temporary array of size d we can addpot the following algorithm to rotate an array

1. Copy the i-th (i=0) item to a temporary variable temp = num[0];

2. Shift all the item of the array from right to left by one position and the array will be

num[] = {4,5,6,7,8,9,1,2,2};

3. Placed the temp value at the last location of the array num[size-1] = temp; Then the array will be

num[] = {4,5,6,7,8,9,1,2,3};

4. Increment the i by 1 and check the value of i

   • if it is less than d, then repeat the step - 1 to 4

   • else terminate

Time Complexity : O(n*d). n for swapping and d is the number of times swapping need to performed.