Rotate Left k cells
public static int [] rotateLeft(int [] source, int k){
int arr[] = copyArray(source, source.length);
int[] temp = new int[arr.length];
for (int i=0; i<arr.length; i++) {
temp[i] = arr[(i + k) % arr.length];
}
for (int i=0; i<arr.length; i++) {
arr[i] = temp[i];
}
return arr;
}