Spiral matrix: Difference between revisions

=={{header|Rust}}==

<lang rust>const VECTORS: [(isize, isize); 4] = [(1, 0), (0, 1), (-1, 0), (0, -1)];

pub fn spiral_matrix(size: usize) -> Vec<Vec<u32>> {

let mut matrix = vec![vec![0; size]; size];

let mut movement = VECTORS.iter().cycle();

let (mut x, mut y, mut n) = (-1, 0, 1..);

for (move_x, move_y) in std::iter::once(size)

.chain((1..size).rev().flat_map(|n| std::iter::repeat(n).take(2)))

.flat_map(|steps| std::iter::repeat(movement.next().unwrap()).take(steps))

{

x += move_x;

y += move_y;

matrix[y as usize][x as usize] = n.next().unwrap();

}

matrix

}

fn main() {

for i in spiral_matrix(4).iter() {

for j in i.iter() {

print!("{:>2} ", j);

}

println!();

}

}</lang>

{{out}}

<pre>

0 1 2 3 4

15 16 17 18 5

14 23 24 19 6

13 22 21 20 7

12 11 10 9 8

</pre>