Program for array rotation

Program for array rotation

METHOD 1

// C program to rotate an array by

// d elements

#include <stdio.h>

/* Function to left Rotate arr[] of size n by 1*/

void leftRotatebyOne(int arr[], int n);

/*Function to left rotate arr[] of size n by d*/

void leftRotate(int arr[], int d, int n)

{

  int i;

  for (i = 0; i < d; i++)

    leftRotatebyOne(arr, n);

}

void leftRotatebyOne(int arr[], int n)

{

  int temp = arr[0], i;

  for (i = 0; i < n-1; i++)

     arr[i] = arr[i+1];

  arr[i] = temp;

}

/* utility function to print an array */

void printArray(int arr[], int n)

{

  int i;

  for (i = 0; i < n; i++)

    printf("%d ", arr[i]);

}

/* Driver program to test above functions */

int main()

{

   int arr[] = {1, 2, 3, 4, 5, 6, 7};

   leftRotate(arr, 2, 7);

   printArray(arr, 7);

   return 0;

}

Output :

3 4 5 6 7 1 2

METHOD 2

#include <stdio.h>

/* function to print an array */

void printArray(int arr[], int size);

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

int gcd(int a,int b);

/*Function to left rotate arr[] of siz n by d*/

void leftRotate(int arr[], int d, int n)

{

  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(1)

    {

      k = j + d;

      if (k >= n)

        k = k - n;

      if (k == i)

        break;

      arr[j] = arr[k];

      j = k;

    }

    arr[j] = temp;

  }

}

/*UTILITY FUNCTIONS*/

/* function to print an array */

void printArray(int arr[], int n)

{

int i;

  for (i = 0; i < n; i++)

    printf("%d ", arr[i]);

}

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

int gcd(int a,int b)

{

   if (b==0)

     return a;

   else

     return gcd(b, a%b);

}

/* Driver program to test above functions */

int main()

{

   int arr[] = {1, 2, 3, 4, 5, 6, 7};

   leftRotate(arr, 2, 7);

   printArray(arr, 7);

   getchar();

   return 0;

}

Output :

3 4 5 6 7 1 2