Given a matrix of size N*M, and a number K. We need to clockwise (or right) rotate each row of matrix K times.
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:
Try It Yourself
// 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 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 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.
# 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# 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.
<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>
<?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)
?>
Output
23 34 12 56 67 45 89 91 78
Time Complexity: O(n*m)
Auxiliary Space: O(m)