Number of Closed Islands | LeetCode

class Solution { public int closedIsland(int[][] grid) { int row = grid.length; int col = grid[0].length; int countIsland = 0; for(int i=0; i<row; i++){ for(int j=0; j<col; j++){ if(grid[i][j]==0 && dfs(grid, i, j)){ countIsland++; } } } return countIsland; } boolean dfs(int grid[][], int i, int j){ if(i<0 || j<0 || i>=grid.length || j>=grid[0].length) return false; if(grid[i][j]==1 || grid[i][j]==2) return true; grid[i][j] = 2; boolean up = dfs(grid, i+1, j); boolean down = dfs(grid, i-1, j); boolean left = dfs(grid, i, j+1); boolean right = dfs(grid, i, j-1); return up && down && left && right; }
}