# Left Rotation in an Array using Java

22:48

__Left Rotation in an Array using Java__
There are two methods implemented by me here :-

1) Using extra Array

- Get new position of a current element using formula.
- Add the element in the new position in a new array.

2) Using same Array:- This is little bit complex

- hold variable at index i.
- find new index for variable.
- hold variable present at new index.
- place variable at index i to this new index.
- assign i to new index variable.
- repeat steps until count is not equal to lenght of an array which simply means all variable got covered.

package Arrays; /* * 12345 to 34512 */ /* * sample input * 5 4(d=4 that is 4 rotations) 1 2 3 4 5 sample output 51234 */ public class LeftRotation { public static void printArray(int[] arr) { for(int i=0;i<arr.length;i++) { System.out.print(" "+arr[i]); } System.out.println(" "); } //method which returns rotated array using extra array public static int[] leftRotate(int[] arr, int rotation) { int temparr[]=new int[arr.length]; int pos; for(int i=0;i<arr.length;i++) { pos=(arr.length+(i-rotation))%arr.length; temparr[pos]=arr[i]; } printArray(temparr); return temparr; } //method which returns rotated array using same array public static int[] leftRotate2(int[] arr, int rotation) { int pos,tempinit,temppos=arr[0],i=0,c=0; while(c!=arr.length){ tempinit=temppos; pos=(arr.length+(i-rotation))%arr.length; temppos=arr[pos]; arr[pos]=tempinit; i=pos; c++; } printArray(arr); return arr; } public static void main(String[] args) { int[] arr={1,2,3,4,5}; leftRotate(arr, 3); leftRotate2(arr, 3); } }

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