54. Spiral Matrix

Given an `m x n` `matrix`, return all elements of the `matrix` in spiral order.

Example 1:

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

Example 2:

```Input: matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
Output: [1,2,3,4,8,12,11,10,9,5,6,7]
```

Constraints:

• `m == matrix.length`
• `n == matrix[i].length`
• `1 <= m, n <= 10`
• `-100 <= matrix[i][j] <= 100`

Rust Solution

``````struct Solution;

enum Direction {
Right,
Down,
Left,
Up,
}
impl Solution {
fn spiral_order(matrix: Vec<Vec<i32>>) -> Vec<i32> {
let n = matrix.len();
if n == 0 {
return vec![];
}
let m = matrix[0].len();
if m == 0 {
return vec![];
}
let mut res: Vec<i32> = vec![];
let mut i = 0;
let mut j = 0;
let mut left = 0;
let mut top = 0;
let mut bottom = n - 1;
let mut right = m - 1;
let mut direction = Direction::Right;
loop {
res.push(matrix[i][j]);
match direction {
Direction::Right => {
if j < right {
j += 1;
} else {
if top < bottom {
top += 1;
direction = Direction::Down;
i += 1;
} else {
break;
}
}
}
Direction::Down => {
if i < bottom {
i += 1;
} else {
if left < right {
right -= 1;
direction = Direction::Left;
j -= 1;
} else {
break;
}
}
}
Direction::Left => {
if j > left {
j -= 1;
} else {
if top < bottom {
bottom -= 1;
direction = Direction::Up;
i -= 1;
} else {
break;
}
}
}
Direction::Up => {
if i > top {
i -= 1;
} else {
if left < right {
left += 1;
direction = Direction::Right;
j += 1;
} else {
break;
}
}
}
}
}
res
}
}

#[test]
fn test() {
let matrix: Vec<Vec<i32>> = vec_vec_i32![[1, 2, 3], [4, 5, 6], [7, 8, 9]];
let res = vec![1, 2, 3, 6, 9, 8, 7, 4, 5];
assert_eq!(Solution::spiral_order(matrix), res);
let matrix: Vec<Vec<i32>> = vec_vec_i32![[3], [2]];
let res = vec![3, 2];
assert_eq!(Solution::spiral_order(matrix), res);
}
``````

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