<h2><a href="https://leetcode.com/problems/number-of-distinct-islands/">694. Number of Distinct Islands</a></h2><h3>Medium</h3><hr><div><p>You are given an <code>m x n</code> binary matrix <code>grid</code>. An island is a group of <code>1</code>'s (representing land) connected <strong>4-directionally</strong> (horizontal or vertical.) You may assume all four edges of the grid are surrounded by water.</p>

<p>An island is considered to be the same as another if and only if one island can be translated (and not rotated or reflected) to equal the other.</p>

<p>Return <em>the number of <b>distinct</b> islands</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/05/01/distinctisland1-1-grid.jpg" style="width: 413px; height: 334px;">
<pre><strong>Input:</strong> grid = [[1,1,0,0,0],[1,1,0,0,0],[0,0,0,1,1],[0,0,0,1,1]]
<strong>Output:</strong> 1
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/05/01/distinctisland1-2-grid.jpg" style="width: 413px; height: 334px;">
<pre><strong>Input:</strong> grid = [[1,1,0,1,1],[1,0,0,0,0],[0,0,0,0,1],[1,1,0,1,1]]
<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;= 50</code></li>
	<li><code>grid[i][j]</code> is either <code>0</code> or <code>1</code>.</li>
</ul>
</div>