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Print array after it is right rotated K times
  • Difficulty Level : Easy
  • Last Updated : 15 Jun, 2020


Given an Array of size N and a values K, around which we need to right rotate the array. How to quickly print the right rotated array?

Examples :

Input: Array[] = {1, 3, 5, 7, 9}, K = 2.
Output: 7 9 1 3 5
Explanation:
After 1st rotation - {9, 1, 3, 5, 7}
After 2nd rotation - {7, 9, 1, 3, 5}

Input: Array[] = {1, 2, 3, 4, 5}, K = 4.
Output: 2 3 4 5 1      

Approach:

  1. We will first take mod of K by N (K = K % N) because after every N rotations array will become the same as the initial array.
  2. Now, we will iterate the array from i = 0 to i = N-1 and check,
    • If i < K, Print rightmost Kth element (a[N + i -K]). Otherwise,
    • Print array after ‘K’ elements (a[i – K]).

Below is the implementation of the above approach.

C++




// C++ implementation of right rotation 
// of an array K number of times
#include<bits/stdc++.h>
using namespace std;
  
// Function to rightRotate array
void RightRotate(int a[], int n, int k)
{
      
    // If rotation is greater 
    // than size of array
    k = k % n;
  
    for(int i = 0; i < n; i++)
    {
       if(i < k)
       {
             
           // Printing rightmost 
           // kth elements
           cout << a[n + i - k] << " ";
       }
       else
       {
             
           // Prints array after
           // 'k' elements
           cout << (a[i - k]) << " ";
       }
    }
    cout << "\n";
}
      
// Driver code
int main()
{
    int Array[] = { 1, 2, 3, 4, 5 };
    int N = sizeof(Array) / sizeof(Array[0]);
    int K = 2;
      
    RightRotate(Array, N, K);
}
  
// This code is contributed by Surendra_Gangwar

Java




// Java Implementation of Right Rotation 
// of an Array K number of times
import java.util.*;
import java.lang.*;
import java.io.*;
  
class Array_Rotation
{
  
// Function to rightRotate array
static void RightRotate(int a[], 
                        int n, int k)
{
      
    // If rotation is greater 
    // than size of array
    k=k%n;
  
    for(int i = 0; i < n; i++)
    {
        if(i<k)
        {
            // Printing rightmost 
            // kth elements
            System.out.print(a[n + i - k] 
                             + " ");
        }
        else
        {
            // Prints array after
            // 'k' elements
            System.out.print(a[i - k] 
                             + " ");
        }
    }
    System.out.println();
}
      
// Driver program
public static void main(String args[])
{
    int Array[] = {1, 2, 3, 4, 5};
    int N = Array.length;
  
    int K = 2;
    RightRotate(Array, N, K);
  
}
}
// This code is contributed by M Vamshi Krishna

Python3




# Python3 implementation of right rotation 
# of an array K number of times
  
# Function to rightRotate array
def RightRotate(a, n, k):
  
    # If rotation is greater 
    # than size of array
    k = k % n;
  
    for i in range(0, n):
  
        if(i < k):
  
            # Printing rightmost 
            # kth elements
            print(a[n + i - k], end = " ");
  
        else:
  
            # Prints array after
            # 'k' elements
            print(a[i - k], end = " ");
  
    print("\n");
  
# Driver code
Array = [ 1, 2, 3, 4, 5 ];
N = len(Array);
K = 2;
      
RightRotate(Array, N, K);
  
# This code is contributed by Code_Mech

C#




// C# implementation of right rotation 
// of an array K number of times
using System;
class GFG{
  
// Function to rightRotate array
static void RightRotate(int []a, 
                        int n, int k)
{
  
    // If rotation is greater 
    // than size of array
    k = k % n;
  
    for(int i = 0; i < n; i++)
    {
       if(i < k)
       {
             
           // Printing rightmost 
           // kth elements
           Console.Write(a[n + i - k] + " ");
       }
       else
       {
             
           // Prints array after
           // 'k' elements
           Console.Write(a[i - k] + " ");
       }
    }
    Console.WriteLine();
}
      
// Driver code
public static void Main(String []args)
{
    int []Array = { 1, 2, 3, 4, 5 };
    int N = Array.Length;
    int K = 2;
      
    RightRotate(Array, N, K);
}
}
  
// This code is contributed by Rohit_ranjan
Output:
4 5 1 2 3

Time complexity : O(n)
Auxiliary Space : O(1)




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