<p>Given an <code>m x n</code> 2D binary grid <code>grid</code> which represents a map of <code>&#39;1&#39;</code>s (land) and <code>&#39;0&#39;</code>s (water), return <em>the number of islands</em>.</p>

<p>An <strong>island</strong> is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> grid = [
  [&quot;1&quot;,&quot;1&quot;,&quot;1&quot;,&quot;1&quot;,&quot;0&quot;],
  [&quot;1&quot;,&quot;1&quot;,&quot;0&quot;,&quot;1&quot;,&quot;0&quot;],
  [&quot;1&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;],
  [&quot;0&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;]
]
<strong>Output:</strong> 1
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> grid = [
  [&quot;1&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;],
  [&quot;1&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;],
  [&quot;0&quot;,&quot;0&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;],
  [&quot;0&quot;,&quot;0&quot;,&quot;0&quot;,&quot;1&quot;,&quot;1&quot;]
]
<strong>Output:</strong> 3
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>m == grid.length</code></li>
	<li><code>n == grid[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 300</code></li>
	<li><code>grid[i][j]</code> is <code>&#39;0&#39;</code> or <code>&#39;1&#39;</code>.</li>
</ul>

class Solution:
    def numIslands(self, grid: List[List[str]]) -> int:
        m = len(grid)
        n = len(grid[0])

        islands = 0
        stack = list()

        for row in range(m):
            print('row %i' % row)
            for column in range(n):
                print('col %i' % column)
                val = grid[row][column]

                if val != '1':
                    continue 

                islands += 1

                stack = list() 
                stack.append((row, column))

                while len(stack):
                    x, y = stack.pop()
                    grid[x][y] = '0'
                    print('loop for x - %i, y - %i' % (x, y))
                    print(stack)

                    # check if there is any neighbor
                    # prev neighbor
                    if (
                        y > 0
                        and grid[x][y-1] == '1'
                    ):
                        stack.append((x, y-1))

                    # upper neighbor 
                    if (
                        x > 0 
                        and grid[x-1][y] == '1'
                    ):
                        stack.append((x-1, y))

                    # next neighbor
                    if (
                        y < (n-1)
                        and grid[x][y+1] == '1'
                    ):
                        stack.append((x, y+1))

                    # bottom neighbor 
                    if (
                        x < (m-1)
                        and grid[x+1][y] == '1'
                    ):
                        stack.append((x+1, y))

        return islands           

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