1568. Minimum number of days to disconnect island

//1568. Minimum number of days to disconnect island

class Solution {
    public int minDays(int[][] grid) {
        if(countIslands(grid) != 1) {
            return 0;
        }

        for(int i = 0; i < grid.length; i++) {
            for(int j = 0; j < grid[0].length; j++) {
                if(grid[i][j] == 1) {
                    grid[i][j] = 0;
                    
                    if(countIslands(grid) != 1) {
                        return 1;
                    }

                    grid[i][j] = 1;
                }
            }
        }

        return 2;
    }

    private int countIslands(int[][] grid) {
        boolean[][] seen = new boolean[grid.length][grid[0].length];
        int islands = 0;

        for(int i = 0; i < grid.length; i++) {
            for(int j = 0; j < grid[0].length; j++) {
                if(grid[i][j] == 1 && !seen[i][j]) {
                    islands++;
                    dfs(grid, i, j, seen);
                }
            }
        }

        return islands;
    }

    private void dfs(int[][] grid, int r, int c, boolean[][] seen) {
        seen[r][c] = true;
        int[][] directions = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
        
        for(int[] dir : directions) {
            int nr = r + dir[0], nc = c + dir[1];
            if(nr >= 0 && nr < grid.length && nc >= 0 && nc < grid[0].length && grid[nr][nc] == 1 && !seen[nr][nc]) {
                dfs(grid, nr, nc, seen);
            }
        }
    }
}