Sunday, June 24, 2018

Rotate Left function in JAVA

Here is an interesting way to solve the problem of Array Left Rotation function:

The left rotation problem as shown on HackerRank:
left rotation operation on an array shifts each of the array's elements  unit to the left. For example, if  left rotations are performed on array , then the array would become .


static int[] rotLeft(int[] a, int d) {
   int[] b = new int[a.length];
   System.arraycopy(a, d, b, 0, (a.length - d));
   System.arraycopy(a, 0, b, (a.length - d), d);
   return b;
}



What happens here is:

  • First, we initialize a new array to hold our shifted values.
  • We then decide where to split the array using the d value, 
  • Then, you copy the old array part by part to the new array and you have a solution.