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Rotate the matrix right by K times

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  • Difficulty Level : Medium
  • Last Updated : 03 Aug, 2022

Given a matrix of size N*M, and a number K. We have to rotate the matrix K times to the right side. 

Examples: 

Input :  N = 3, M = 3, K = 2
         12 23 34
         45 56 67
         78 89 91 

Output : 23 34 12
         56 67 45
         89 91 78 


Input :  N = 2, M = 2, K = 2
         1 2
         3 4
         
Output : 1 2
         3 4

A simple yet effective approach is to consider each row of the matrix as an array and perform an array rotation. This can be done by copying the elements from K to end of array to starting of array using temporary array. And then the remaining elements from start to K-1 to end of the array.

Lets take an example: 
 


 

Implementation:

C++




// CPP program to rotate a matrix right by k times
#include <iostream>
 
// size of matrix
#define M 3
#define N 3
 
using namespace std;
 
// function to rotate matrix by k times
void rotateMatrix(int matrix[][M], int k) {
  // temporary array of size M
  int temp[M];
 
  // within the size of matrix
  k = k % M;
 
  for (int i = 0; i < N; i++) {
 
    // copy first M-k elements to temporary array
    for (int t = 0; t < M - k; t++)
      temp[t] = matrix[i][t];
 
    // copy the elements from k to end to starting
    for (int j = M - k; j < M; j++)
      matrix[i][j - M + k] = matrix[i][j];
 
    // copy elements from temporary array to end
    for (int j = k; j < M; j++)
      matrix[i][j] = temp[j - k];
  }
}
 
// function to display the matrix
void displayMatrix(int matrix[][M]) {
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < M; j++)
      cout << matrix[i][j] << " ";
    cout << endl;
  }
}
 
// Driver's code
int main() {
  int matrix[N][M] = {{12, 23, 34},
                     {45, 56, 67},
                     {78, 89, 91}};
  int k = 2;
 
  // rotate matrix by k
  rotateMatrix(matrix, k);
 
  // display rotated matrix
  displayMatrix(matrix);
 
  return 0;
}

C




// C program to rotate a matrix right by k times
#include <stdio.h>
 
// size of matrix
#define M 3
#define N 3
 
// function to rotate matrix by k times
void rotateMatrix(int matrix[][M], int k)
{
   
  // temporary array of size M
  int temp[M];
 
  // within the size of matrix
  k = k % M;
 
  for (int i = 0; i < N; i++) {
 
    // copy first M-k elements to temporary array
    for (int t = 0; t < M - k; t++)
      temp[t] = matrix[i][t];
 
    // copy the elements from k to end to starting
    for (int j = M - k; j < M; j++)
      matrix[i][j - M + k] = matrix[i][j];
 
    // copy elements from temporary array to end
    for (int j = k; j < M; j++)
      matrix[i][j] = temp[j - k];
  }
}
 
// function to display the matrix
void displayMatrix(int matrix[][M]) {
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < M; j++)
      printf("%d ",matrix[i][j]);
    printf("\n");
  }
}
 
// Driver's code
int main() {
  int matrix[N][M] = {{12, 23, 34},
                     {45, 56, 67},
                     {78, 89, 91}};
  int k = 2;
 
  // rotate matrix by k
  rotateMatrix(matrix, k);
 
  // display rotated matrix
  displayMatrix(matrix);
 
  return 0;
}
 
// This code is contributed by kothavvsaakash.

Java




// Java program to rotate a matrix
// right by k times
 
class GFG
{
    // size of matrix
    static final int M=3;
    static final int N=3;
     
    // function to rotate matrix by k times
    static void rotateMatrix(int matrix[][], int k)
    {
        // temporary array of size M
        int temp[]=new int[M];
         
        // within the size of matrix
        k = k % M;
         
        for (int i = 0; i < N; i++)
        {
         
            // copy first M-k elements
            // to temporary array
            for (int t = 0; t < M - k; t++)
            temp[t] = matrix[i][t];
         
            // copy the elements from k
            // to end to starting
            for (int j = M - k; j < M; j++)
            matrix[i][j - M + k] = matrix[i][j];
         
            // copy elements from
            // temporary array to end
            for (int j = k; j < M; j++)
            matrix[i][j] = temp[j - k];
        }
    }
     
    // function to display the matrix
    static void displayMatrix(int matrix[][])
    {
        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j < M; j++)
            System.out.print(matrix[i][j] + " ");
            System.out.println();
        }
    }
     
    // Driver code
    public static void main (String[] args)
    {
        int matrix[][] = {{12, 23, 34},
                        {45, 56, 67},
                        {78, 89, 91}};
    int k = 2;
     
    // rotate matrix by k
    rotateMatrix(matrix, k);
     
    // display rotated matrix
    displayMatrix(matrix);
    }
}
 
// This code is contributed by Anant Agarwal.

Python3




# Python program to rotate
# a matrix right by k times
 
# size of matrix
M = 3
N = 3
matrix = [[12, 23, 34],
          [45, 56, 67],
          [78, 89, 91]]
 
# function to rotate
# matrix by k times
def rotateMatrix(k) :
 
    global M, N, matrix
     
    # temporary array
    # of size M
    temp = [0] * M
     
    # within the size
    # of matrix
    k = k % M
     
    for i in range(0, N) :
     
        # copy first M-k elements
        # to temporary array
        for t in range(0, M - k) :
            temp[t] = matrix[i][t]
     
        # copy the elements from
        # k to end to starting
        for j in range(M - k, M) :
            matrix[i][j - M + k] = matrix[i][j]
     
        # copy elements from
        # temporary array to end
        for j in range(k, M) :
            matrix[i][j] = temp[j - k]
     
# function to display
# the matrix
def displayMatrix() :
 
    global M, N, matrix
    for i in range(0, N) :
     
        for j in range(0, M) :
            print ("{} " .
                   format(matrix[i][j]), end = "")
        print ()
 
# Driver code
k = 2
 
# rotate matrix by k
rotateMatrix(k)
 
# display rotated matrix
displayMatrix()
 
# This code is contributed by
# Manish Shaw(manishshaw1)

C#




// C# program to rotate a 
// matrix right by k times
using System;
 
class GFG {
     
    // size of matrix
    static int M=3;
    static int N=3;
     
    // function to rotate matrix by k times
    static void rotateMatrix(int [,] matrix,
                             int k)
    {
         
        // temporary array of size M
        int [] temp=new int[M];
         
        // within the size of matrix
        k = k % M;
         
        for (int i = 0; i < N; i++)
        {
         
            // copy first M-k elements
            // to temporary array
            for (int t = 0; t < M - k; t++)
            temp[t] = matrix[i, t];
         
            // copy the elements from k
            // to end to starting
            for (int j = M - k; j < M; j++)
            matrix[i, j - M + k] = matrix[i, j];
         
            // copy elements from
            // temporary array to end
            for (int j = k; j < M; j++)
            matrix[i, j] = temp[j - k];
        }
    }
     
    // function to display the matrix
    static void displayMatrix(int [,] matrix)
    {
        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j < M; j++)
            Console.Write(matrix[i, j] + " ");
            Console.WriteLine();
        }
    }
     
    // Driver code
    public static void Main ()
    {
        int [,] matrix = {{12, 23, 34},
                          {45, 56, 67},
                          {78, 89, 91}};
        int k = 2;
         
        // rotate matrix by k
        rotateMatrix(matrix, k);
         
        // display rotated matrix
        displayMatrix(matrix);
    }
}
 
// This code is contributed by KRV.

PHP




<?php
// PHP program to rotate
// a matrix right by k times
 
// size of matrix
$M = 3;
$N = 3;
 
// function to rotate
// matrix by k times
function rotateMatrix(&$matrix, $k)
{
    global $M, $N;
     
    // temporary array
    // of size M
    $temp = array();
     
    // within the size
    // of matrix
    $k = $k % $M;
     
    for ($i = 0; $i < $N; $i++)
    {
     
        // copy first M-k elements
        // to temporary array
        for ($t = 0;
             $t < $M - $k; $t++)
        $temp[$t] = $matrix[$i][$t];
     
        // copy the elements from
        // k to end to starting
        for ($j = $M - $k;
             $j < $M; $j++)
        $matrix[$i][$j - $M + $k] =
                    $matrix[$i][$j];
     
        // copy elements from
        // temporary array to end
        for ($j = $k; $j < $M; $j++)
        $matrix[$i][$j] = $temp[$j - $k];
    }
}
 
// function to display
// the matrix
function displayMatrix(&$matrix)
{
    global $M, $N;
    for ($i = 0; $i < $N; $i++)
    {
        for ($j = 0; $j < $M; $j++)
        echo ($matrix[$i][$j]." ");
        echo ("\n");
    }
}
 
// Driver code
$matrix = array(array(12, 23, 34),
                array(45, 56, 67),
                array(78, 89, 91));
$k = 2;
 
// rotate matrix by k
rotateMatrix($matrix, $k);
 
// display rotated matrix
displayMatrix($matrix);
 
// This code is contributed by
// Manish Shaw(manishshaw1)
?>

Javascript




<script>
 
// Javascript program to rotate a matrix
// right by k times   
 
 
// size of matrix
    var M = 3;
     var N = 3;
 
    // function to rotate matrix by k times
    function rotateMatrix(matrix , k)
    {
        // temporary array of size M
        var temp = Array(M).fill(0);
 
        // within the size of matrix
        k = k % M;
 
        for (i = 0; i < N; i++) {
 
            // copy first M-k elements
            // to temporary array
            for (t = 0; t < M - k; t++)
                temp[t] = matrix[i][t];
 
            // copy the elements from k
            // to end to starting
            for (j = M - k; j < M; j++)
                matrix[i][j - M + k] = matrix[i][j];
 
            // copy elements from
            // temporary array to end
            for (j = k; j < M; j++)
                matrix[i][j] = temp[j - k];
        }
    }
 
    // function to display the matrix
    function displayMatrix(matrix) {
        for (i = 0; i < N; i++) {
            for (j = 0; j < M; j++)
                document.write(matrix[i][j] + " ");
            document.write("<br/>");
        }
    }
 
    // Driver code
     
        var matrix = [
        [ 12, 23, 34 ],
        [ 45, 56, 67 ],
        [ 78, 89, 91 ] ];
        var k = 2;
 
        // rotate matrix by k
        rotateMatrix(matrix, k);
 
        // display rotated matrix
        displayMatrix(matrix);
 
// This code contributed by umadevi9616
 
</script>

Output: 

23 34 12 
56 67 45 
89 91 78

 

Time Complexity: O(n*m)
Auxiliary Space: O(m)


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