rustgym 0.2.0

struct Solution;

impl Solution {
    fn closed_island(mut grid: Vec<Vec<i32>>) -> i32 {
        let mut res = 0;
        let n = grid.len();
        let m = grid[0].len();
        for i in 0..n {
            for j in 0..m {
                if grid[i][j] == 0 && Self::dfs(i, j, &mut grid, n, m) {
                    res += 1;
                }
            }
        }
        res
    }

    fn dfs(i: usize, j: usize, grid: &mut Vec<Vec<i32>>, n: usize, m: usize) -> bool {
        grid[i][j] = 1;
        let top = if i > 0 {
            if grid[i - 1][j] == 1 {
                true
            } else {
                Self::dfs(i - 1, j, grid, n, m)
            }
        } else {
            false
        };
        let left = if j > 0 {
            if grid[i][j - 1] == 1 {
                true
            } else {
                Self::dfs(i, j - 1, grid, n, m)
            }
        } else {
            false
        };
        let bottom = if i + 1 < n {
            if grid[i + 1][j] == 1 {
                true
            } else {
                Self::dfs(i + 1, j, grid, n, m)
            }
        } else {
            false
        };
        let right = if j + 1 < m {
            if grid[i][j + 1] == 1 {
                true
            } else {
                Self::dfs(i, j + 1, grid, n, m)
            }
        } else {
            false
        };
        top && left && bottom && right
    }
}

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