Java Program to Left Rotate the Elements of an Array

In Java, left rotation of an array involves shifting its elements to the left by a given number of positions, with the first elements moving around to the end. There are different ways to left rotate the elements of an array in Java.

Example:

We can use a temporary array to rotate the array left by "d" positions. This approach is useful when the array size is not too large. Also, the temporary array does not impact the memory constraints.

3 4 5 6 7 1 2 

Other Ways to Left Rotate the Elements of an Array

Rotating Elements One-by-One

In this approach, we rotate the array to left by one position at each step. After performing this operation "d" times, the array is rotated to the left by "d" positions. This method is simple and effective for small values of "d".

Example:

3 4 5 6 7 1 2 

Using Juggling Algorithm

In this approach, it optimizes the rotation by using the GCD of "N" and "d" to divide the arrays into sets. Here, each set will rotate internally. It is an efficient approach for large arrays because it reduces the number of element moves.

Steps:

• Calculate d % N to ensure rotations stay within array bounds.
• Compute the GCD of N and d to determine the number of sets.
• For each set, store the set's first element in a temporary variable.
• Rotate elements within the set by moving each element d positions left.
• Assign the temporary variable to the last position in the set.

Example: