rustgym 0.2.0

struct Solution;

impl Solution {
    fn min_days(mut grid: Vec<Vec<i32>>) -> i32 {
        let n = grid.len();
        let m = grid[0].len();

        if Self::islands(&grid, n, m) != 1 {
            return 0;
        }

        for i in 0..n {
            for j in 0..m {
                if grid[i][j] == 1 {
                    grid[i][j] = 0;
                    if Self::islands(&grid, n, m) > 1 {
                        return 1;
                    }
                    grid[i][j] = 1;
                }
            }
        }

        2
    }

    fn islands(grid: &[Vec<i32>], n: usize, m: usize) -> i32 {
        let mut visited = vec![vec![false; m]; n];
        let mut res = 0;
        for i in 0..n {
            for j in 0..m {
                if !visited[i][j] && grid[i][j] == 1 {
                    res += 1;
                    visited[i][j] = true;
                    Self::dfs(i, j, &mut visited, grid, n, m);
                }
            }
        }
        res
    }

    fn dfs(
        i: usize,
        j: usize,
        visited: &mut Vec<Vec<bool>>,
        grid: &[Vec<i32>],
        n: usize,
        m: usize,
    ) {
        if i > 0 && grid[i - 1][j] == 1 && !visited[i - 1][j] {
            visited[i - 1][j] = true;
            Self::dfs(i - 1, j, visited, grid, n, m);
        }
        if j > 0 && grid[i][j - 1] == 1 && !visited[i][j - 1] {
            visited[i][j - 1] = true;
            Self::dfs(i, j - 1, visited, grid, n, m);
        }
        if i + 1 < n && grid[i + 1][j] == 1 && !visited[i + 1][j] {
            visited[i + 1][j] = true;
            Self::dfs(i + 1, j, visited, grid, n, m);
        }
        if j + 1 < m && grid[i][j + 1] == 1 && !visited[i][j + 1] {
            visited[i][j + 1] = true;
            Self::dfs(i, j + 1, visited, grid, n, m);
        }
    }
}

#[test]
fn test() {
    let grid = vec_vec_i32![[0, 1, 1, 0], [0, 1, 1, 0], [0, 0, 0, 0]];
    let res = 2;
    assert_eq!(Solution::min_days(grid), res);
    let grid = vec_vec_i32![[1, 1]];
    let res = 2;
    assert_eq!(Solution::min_days(grid), res);
    let grid = vec_vec_i32![[1, 0, 1, 0]];
    let res = 0;
    assert_eq!(Solution::min_days(grid), res);
    let grid = vec_vec_i32![
        [1, 1, 0, 1, 1],
        [1, 1, 1, 1, 1],
        [1, 1, 0, 1, 1],
        [1, 1, 0, 1, 1]
    ];
    let res = 1;
    assert_eq!(Solution::min_days(grid), res);
    let grid = vec_vec_i32![
        [1, 1, 0, 1, 1],
        [1, 1, 1, 1, 1],
        [1, 1, 0, 1, 1],
        [1, 1, 1, 1, 1]
    ];
    let res = 2;
    assert_eq!(Solution::min_days(grid), res);
}