content: package LeetCode.Medium.RotateImage;
  
  /*
    48. Rotate Image
  
    You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).
  
    You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
  
  
    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]]
  
    Example 3:
    Input: matrix = [[1]]
    Output: [[1]]
  
    Example 4:
    Input: matrix = [[1,2],[3,4]]
    Output: [[3,1],[4,2]]
  
  
    Constraints:
    matrix.length == n
    matrix[i].length == n
    1 <= n <= 20
    -1000 <= matrix[i][j] <= 1000
  */
  
  public class Solution {
    public void rotate(int[][] matrix) {
      int n = matrix.length;
  
      // First, swap the inverse diagonals
      for (int i = 0; i < n; i++)
        for (int j = i; j < n; j++) {
          int temp = matrix[i][j];
          matrix[i][j] = matrix[j][i];
          matrix[j][i] = temp;
        }
  
      // Then, swap the first and
      // last cells on each row
      for (int i = 0; i < n; i++)
        for (int j = 0; j < (n / 2); j++) {
          int temp = matrix[i][j];
          matrix[i][j] = matrix[i][n - 1 - j];
          matrix[i][n - 1 - j] = temp;
        }
    }
  
    public static void main(String[] args) {
      Solution solution = new Solution();
  
      int[][] matrix =
          new int[][] {
            {5, 1, 9, 11},
            {2, 4, 8, 10},
            {13, 3, 6, 7},
            {15, 14, 12, 16}
          };
  
      solution.rotate(matrix);
  
      for (int i = 0; i < matrix.length; i++) {
        for (int j = 0; j < matrix[i].length; j++) System.out.print(matrix[i][j] + " ");
  
        System.out.println();
      }
    }
  }
  