Class Solution
java.lang.Object
g1901_2000.s1992_find_all_groups_of_farmland.Solution
1992 - Find All Groups of Farmland.<p>Medium</p>
<p>You are given a <strong>0-indexed</strong> <code>m x n</code> binary matrix <code>land</code> where a <code>0</code> represents a hectare of forested land and a <code>1</code> represents a hectare of farmland.</p>
<p>To keep the land organized, there are designated rectangular areas of hectares that consist <strong>entirely</strong> of farmland. These rectangular areas are called <strong>groups</strong>. No two groups are adjacent, meaning farmland in one group is <strong>not</strong> four-directionally adjacent to another farmland in a different group.</p>
<p><code>land</code> can be represented by a coordinate system where the top left corner of <code>land</code> is <code>(0, 0)</code> and the bottom right corner of <code>land</code> is <code>(m-1, n-1)</code>. Find the coordinates of the top left and bottom right corner of each <strong>group</strong> of farmland. A <strong>group</strong> of farmland with a top left corner at <code>(r<sub>1</sub>, c<sub>1</sub>)</code> and a bottom right corner at <code>(r<sub>2</sub>, c<sub>2</sub>)</code> is represented by the 4-length array <code>[r<sub>1</sub>, c<sub>1</sub>, r<sub>2</sub>, c<sub>2</sub>].</code></p>
<p>Return <em>a 2D array containing the 4-length arrays described above for each <strong>group</strong> of farmland in</em> <code>land</code><em>. If there are no groups of farmland, return an empty array. You may return the answer in <strong>any order</strong></em>.</p>
<p><strong>Example 1:</strong></p>
<p><img src="https://assets.leetcode.com/uploads/2021/07/27/screenshot-2021-07-27-at-12-23-15-copy-of-diagram-drawio-diagrams-net.png" alt="" /></p>
<p><strong>Input:</strong> land = [[1,0,0],[0,1,1],[0,1,1]]</p>
<p><strong>Output:</strong> [[0,0,0,0],[1,1,2,2]]</p>
<p><strong>Explanation:</strong></p>
<p>The first group has a top left corner at land[0][0] and a bottom right corner at land[0][0].</p>
<p>The second group has a top left corner at land[1][1] and a bottom right corner at land[2][2].</p>
<p><strong>Example 2:</strong></p>
<p><img src="https://assets.leetcode.com/uploads/2021/07/27/screenshot-2021-07-27-at-12-30-26-copy-of-diagram-drawio-diagrams-net.png" alt="" /></p>
<p><strong>Input:</strong> land = [[1,1],[1,1]]</p>
<p><strong>Output:</strong> <a href="0,0,1,1">0,0,1,1</a></p>
<p><strong>Explanation:</strong></p>
<p>The first group has a top left corner at land[0][0] and a bottom right corner at land[1][1].</p>
<p><strong>Example 3:</strong></p>
<p><img src="https://assets.leetcode.com/uploads/2021/07/27/screenshot-2021-07-27-at-12-32-24-copy-of-diagram-drawio-diagrams-net.png" alt="" /></p>
<p><strong>Input:</strong> land = [[0]]</p>
<p><strong>Output:</strong> []</p>
<p><strong>Explanation:</strong> There are no groups of farmland.</p>
<p><strong>Constraints:</strong></p>
<ul>
<li><code>m == land.length</code></li>
<li><code>n == land[i].length</code></li>
<li><code>1 <= m, n <= 300</code></li>
<li><code>land</code> consists of only <code>0</code>’s and <code>1</code>’s.</li>
<li>Groups of farmland are <strong>rectangular</strong> in shape.</li>
</ul>
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Constructor Summary
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Constructor Details
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Solution
public Solution()
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Method Details
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findFarmland
public int[][] findFarmland(int[][] land)
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