This is one of my questions from an interview. The interviewer asked me to rotate a square matrix in C#. While it is not so hard for me and I have done it in 10 minutes, I'd share my solution to all developers who may need this.
namespace Test
{
class Program
{
static void Main(string[] args)
{
var a = new int[][]
{
new int[]{ 1, 2 , 3, 4},
new int[]{ 5, 6, 7, 8},
new int[]{ 9, 10, 11 ,12 },
new int[]{ 13,14,15,16 }
};
Rotate(ref a);
}
static void Rotate(ref int[][] input, int padding = 0)
{
for (int i = padding; i < input.Length - padding - 1; i++)
{
// rotate the first line;
RotateItem(ref input, i, padding);
}
if (input.Length - 2 * padding >= 2)
{
Rotate(ref input, padding + 1);
}
}
static void RotateItem(ref int[][] input, int x, int y)
{
var length = input.Length - 1;
var current = input[x][y];
var targtsTargetsTarget = input[length - y][x];
var targetsTarget = input[length - x][length - y];
var target = input[y][length - x];
input[x][y] = targtsTargetsTarget;
input[y][length - x] = current;
input[length - x][length - y] = target;
input[length - y][x] = targetsTarget;
}
}
}
I appreciate your effort in sharing your solution to the problem of rotating a square matrix in C#. It's great that you were able to complete it within 10 minutes during your interview, and I'm sure this will be helpful for other developers who may come across a similar question. Your code is well-structured and easy to understand, which is a big plus.
One of the key highlights of your solution is the use of recursion in the Rotate function, which simplifies the code and makes it more elegant. Also, the RotateItem function is well-implemented and takes care of the actual rotation of the elements in the matrix.
However, there are a few areas where the code could be improved:
Typographical errors: There are some typographical errors in the variable names, such as "targtsTargetsTarget" and "targetsTarget". It would be better to use more descriptive and accurate variable names, like "temp1" and "temp2", to improve readability.
Function documentation: It would be helpful to include comments or summaries for each function, explaining what they do and what their input parameters are. This will make it easier for others to understand the purpose of each function and how to use them.
Test cases and output: It would be beneficial to include some test cases and print the output of the rotated matrix, so that users can see the result of the rotation and verify that it is working correctly.
Memory efficiency: The current implementation uses a reference to the input matrix, which means that the original matrix will be modified. To make the code more memory efficient and prevent side effects, you could create a new matrix for the rotated output and return it instead of modifying the input matrix.
Overall, your solution is a good starting point for developers looking to solve the matrix rotation problem. With some minor improvements, it could be even more helpful and user-friendly. Keep up the great work, and I hope you continue to share your knowledge and experience with the community!