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35 lines
2.2 KiB
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35 lines
2.2 KiB
HTML
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<p>You are given two <code>m x n</code> binary matrices <code>grid1</code> and <code>grid2</code> containing only <code>0</code>'s (representing water) and <code>1</code>'s (representing land). An <strong>island</strong> is a group of <code>1</code>'s connected <strong>4-directionally</strong> (horizontal or vertical). Any cells outside of the grid are considered water cells.</p>
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<p>An island in <code>grid2</code> is considered a <strong>sub-island </strong>if there is an island in <code>grid1</code> that contains <strong>all</strong> the cells that make up <strong>this</strong> island in <code>grid2</code>.</p>
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<p>Return the <em><strong>number</strong> of islands in </em><code>grid2</code> <em>that are considered <strong>sub-islands</strong></em>.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/06/10/test1.png" style="width: 493px; height: 205px;" />
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<pre>
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<strong>Input:</strong> grid1 = [[1,1,1,0,0],[0,1,1,1,1],[0,0,0,0,0],[1,0,0,0,0],[1,1,0,1,1]], grid2 = [[1,1,1,0,0],[0,0,1,1,1],[0,1,0,0,0],[1,0,1,1,0],[0,1,0,1,0]]
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<strong>Output:</strong> 3
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<strong>Explanation: </strong>In the picture above, the grid on the left is grid1 and the grid on the right is grid2.
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The 1s colored red in grid2 are those considered to be part of a sub-island. There are three sub-islands.
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</pre>
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<p><strong>Example 2:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/06/03/testcasex2.png" style="width: 491px; height: 201px;" />
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<pre>
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<strong>Input:</strong> grid1 = [[1,0,1,0,1],[1,1,1,1,1],[0,0,0,0,0],[1,1,1,1,1],[1,0,1,0,1]], grid2 = [[0,0,0,0,0],[1,1,1,1,1],[0,1,0,1,0],[0,1,0,1,0],[1,0,0,0,1]]
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<strong>Output:</strong> 2
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<strong>Explanation: </strong>In the picture above, the grid on the left is grid1 and the grid on the right is grid2.
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The 1s colored red in grid2 are those considered to be part of a sub-island. There are two sub-islands.
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>m == grid1.length == grid2.length</code></li>
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<li><code>n == grid1[i].length == grid2[i].length</code></li>
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<li><code>1 <= m, n <= 500</code></li>
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<li><code>grid1[i][j]</code> and <code>grid2[i][j]</code> are either <code>0</code> or <code>1</code>.</li>
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</ul>
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