1030. Matrix Cells in Distance Order

We are given a matrix with `R` rows and `C` columns has cells with integer coordinates `(r, c)`, where `0 <= r < R` and `0 <= c < C`.

Additionally, we are given a cell in that matrix with coordinates `(r0, c0)`.

Return the coordinates of all cells in the matrix, sorted by their distance from `(r0, c0)` from smallest distance to largest distance.  Here, the distance between two cells `(r1, c1)` and `(r2, c2)` is the Manhattan distance, `|r1 - r2| + |c1 - c2|`.  (You may return the answer in any order that satisfies this condition.)

Example 1:

```Input: R = 1, C = 2, r0 = 0, c0 = 0
Output: [[0,0],[0,1]]
Explanation: The distances from (r0, c0) to other cells are: [0,1]
```

Example 2:

```Input: R = 2, C = 2, r0 = 0, c0 = 1
Output: [[0,1],[0,0],[1,1],[1,0]]
Explanation: The distances from (r0, c0) to other cells are: [0,1,1,2]
The answer [[0,1],[1,1],[0,0],[1,0]] would also be accepted as correct.
```

Example 3:

```Input: R = 2, C = 3, r0 = 1, c0 = 2
Output: [[1,2],[0,2],[1,1],[0,1],[1,0],[0,0]]
Explanation: The distances from (r0, c0) to other cells are: [0,1,1,2,2,3]
There are other answers that would also be accepted as correct, such as [[1,2],[1,1],[0,2],[1,0],[0,1],[0,0]].
```

Note:

1. `1 <= R <= 100`
2. `1 <= C <= 100`
3. `0 <= r0 < R`
4. `0 <= c0 < C`

1030. Matrix Cells in Distance Order
``````struct Solution;

impl Solution {
fn all_cells_dist_order(r: i32, c: i32, r0: i32, c0: i32) -> Vec<Vec<i32>> {
let mut cells: Vec<Vec<i32>> = vec![];
for i in 0..r {
for j in 0..c {
cells.push(vec![i, j]);
}
}
cells.sort_unstable_by_key(|v| (v[0] - r0).abs() + (v[1] - c0).abs());
cells
}
}

#[test]
fn test() {
let r = 1;
let c = 2;
let r0 = 0;
let c0 = 0;
let res: Vec<Vec<i32>> = vec_vec_i32![[0, 0], [0, 1]];
assert_eq!(Solution::all_cells_dist_order(r, c, r0, c0), res);
let r = 2;
let c = 2;
let r0 = 0;
let c0 = 1;
let res: Vec<Vec<i32>> = vec_vec_i32![[0, 1], [0, 0], [1, 1], [1, 0]];
assert_eq!(Solution::all_cells_dist_order(r, c, r0, c0), res);
let r = 2;
let c = 3;
let r0 = 1;
let c0 = 2;
let res: Vec<Vec<i32>> = vec_vec_i32![[1, 2], [0, 2], [1, 1], [0, 1], [1, 0], [0, 0]];
assert_eq!(Solution::all_cells_dist_order(r, c, r0, c0), res);
}
``````