- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to rotate a matrix of size n*n to 90-degree k times using C#?
The entire matrix needs to be rotated k number of times. In a matrix there is a total of n/2 squares in n*n matrix and we can process each square one at a time using nested loop. In each square, elements are moving in a cycle of 4 elements then we swap the elements involved in an anticlockwise direction for each cycle.
Element at position (n-1-j,i) will go to position(i,j)
Element at position (i,j) will go to position(j,n-1-i)
Element at position (j,n-1-i) will go to position(n-1-i,n-1-j)
Element at position (n-1-i,n-1-j) will go to position(n-1-j,i)
Example
using System; using System.Text; namespace ConsoleApplication{ public class Matrix{ public void RotateMatrixByKTimes(int[,] matrix, int numberOftimes){ int n = matrix.GetLength(0); for (int k = 0; k < numberOftimes; k++){ for (int i = 0; i < n / 2; i++){ for (int j = i; j < n - i - 1; j++){ int top = matrix[i, j]; //MOve left to top matrix[i, j] = matrix[n - 1 - j, i]; //Move bottom to left matrix[n - 1 - j, i] = matrix[n - i - 1, n - 1 - j]; //Move right to bottom matrix[n - i - 1, n - 1 - j] = matrix[j, n - i - 1]; //Move top to right matrix[j, n - i - 1] = top; } } } for (int i = 0; i < n; i++){ StringBuilder s = new StringBuilder(); for (int j = 0; j < n; j++){ s.Append(matrix[i, j] + " "); } Console.WriteLine(s); s = null; } } } class Program{ static void Main(string[] args){ Matrix m = new Matrix(); int[,] matrix = { { 5, 1, 9, 11 }, { 2, 4, 8, 10 }, { 13, 3, 6, 7 }, { 15, 14, 12, 16 } }; m.RotateMatrixByKTimes(matrix, 2); } } }
Output
16 12 14 15 7 6 3 13 10 8 4 2 11 9 1 5
Advertisements