解答

1. fn transpose(matrix: [[i32; 3]; 3]) -> [[i32; 3]; 3] {
2. let mut result = [[0; 3]; 3];
3. for i in 0..3 {
4. for j in 0..3 {
5. result[j][i] = matrix[i][j];
6. }
7. }
8. result
9. }

11. #[test]
12. fn test_transpose() {
13. let matrix = [
14. [101, 102, 103], //
15. [201, 202, 203],
16. [301, 302, 303],
17. ];
18. let transposed = transpose(matrix);
19. assert_eq!(
20. transposed,
21. [
22. [101, 201, 301], //
23. [102, 202, 302],
24. [103, 203, 303],
25. ]
26. );
27. }

29. fn main() {
30. let matrix = [
31. [101, 102, 103], // <-- the comment makes rustfmt add a newline
32. [201, 202, 203],
33. [301, 302, 303],
34. ];

36. println!("matrix: {:#?}", matrix);
37. let transposed = transpose(matrix);
38. println!("transposed: {:#?}", transposed);
39. }