6.Rotate Image

You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise) in place.

Example 1:
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [[7,4,1],[8,5,2],[9,6,3]]

Example 2:
Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]]
Output: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]

Solution :

Approach: Find the transpose of the matrix. Swap the Elements.

class Solution
{
public:
    void rotate(vector<vector<int>> &matrix)
    {
        int n = matrix.size();
        int temp;
        //Find the Transpose
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < n; j++)
            {
                if (i < j)
                {
                    temp = matrix[i][j];
                    matrix[i][j] = matrix[j][i];
                    matrix[j][i] = temp;
                }
            }
        }

         //Swap the values
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < n / 2; j++)
            {
                temp = matrix[i][j];
                matrix[i][j] = matrix[i][n - 1 - j];
                matrix[i][n - 1 - j] = temp;
            }
        }
    }
};