Arrays: Left Rotation

Check out the resources on the page's right side to learn more about arrays. The video tutorial is by Gayle Laakmann McDowell, author of the best-selling interview book Cracking the Coding Interview.

A 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 .

Given an array  of  integers and a number, , perform  left rotations on the array. Return the updated array to be printed as a single line of space-separated integers.

Solution :- 

 static int[] leftRotate(int[] arr, int d)

        {

            var n = arr.Length;

            int i, j, k, temp;

            for (i = 0; i < gcd(d, n); i++)

            {

                /* move i-th values of blocks */

                temp = arr[i];

                j = i;

                while (true)

                {

                    k = j + d;

                    if (k >= n)

                        k = k - n;

                    if (k == i)

                        break;

                    arr[j] = arr[k];

                    j = k;

                }

                arr[j] = temp;

            }

            return arr;

        }

        /* Fuction to get gcd of a and b*/

        static int gcd(int a, int b)

        {

            if (b == 0)

                return a;

            return gcd(b, a % b);

        }