class Solution:
    def numIslands(self, grid: List[List[str]]) -> int:
        if grid is None or len(grid) is 0:
            return 0
        row_count = len(grid)
        col_count = len(grid[0])
        visited = [[0 for _ in range(col_count)] for _ in range(row_count)]
        islands = 0
        for row_idx in range(len(visited)):
            for col_idx in range(len(visited[row_idx])):
                if not visited[row_idx][col_idx]:
                    # haven't visited this cell before
                    # find current cell in original
                    curr_cell = grid[row_idx][col_idx]
                    if curr_cell is "1":
                        # if 1, new island has been found
                        islands += 1
                        # now must find all connecting land elements
                        lands = [(row_idx, col_idx)]
                        while lands:
                            curr_land = lands.pop()
                            associated_row = curr_land[0]
                            associated_col = curr_land[1]
                            if grid[associated_row][associated_col] is "1":
                                if not visited[associated_row][associated_col]:
                                    visited[associated_row][associated_col] = 1
                                    # go through these neighbors and add to lands
                                    look_up = associated_row - 1
                                    look_down = associated_row + 1
                                    look_left = associated_col - 1
                                    look_right = associated_col + 1
                                    if look_up >= 0 and look_up < row_count:
                                        lands.append((look_up, associated_col))
                                    if look_down >= 0 and look_down < row_count:
                                        lands.append((look_down, associated_col))
                                    if look_left >= 0 and look_left < col_count:
                                        lands.append((associated_row, look_left))
                                    if look_right >= 0 and look_right < col_count:
                                        lands.append((associated_row, look_right))
        return islands