48 Rotate Image

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]]

 

Constraints:

n == matrix.length == matrix[i].length
1 <= n <= 20
-1000 <= matrix[i][j] <= 1000

impl Solution {
    pub fn rotate(matrix: &mut Vec<Vec<i32>>) {
        let l = matrix.len() - 1;
        if l == 0 {
            return;
        }

        fn recurse(i: usize, j: usize, matrix: &mut Vec<Vec<i32>>, val: i32) {
            if matrix[i][j] > 1000 || matrix[i][j] < -1000 {
                return;
            }
            let old = matrix[i][j];
            matrix[i][j] = val * 2001;
            let l = matrix.len() - 1;
            recurse(j, l - i, matrix, old);
        }

        for i in 0..matrix.len() {
            for j in 0..matrix.len() {
                if matrix[i][j] <= 1000 && matrix[i][j] >= -1000 {
                    recurse(j, l - i, matrix, matrix[i][j]);
                }
            }
        }

        for i in 0..matrix.len() {
            for j in 0..matrix.len() {
                matrix[i][j] = matrix[i][j] / 2001;
            }
        }
    }
}