C++ Program to Rotate the matrix right by K times
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:
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; } |
Output:
23 34 12 56 67 45 89 91 78
Time Complexity: O(N*M)
Auxiliary Space: O(M)
Please refer complete article on Rotate the matrix right by K times for more details!