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39 lines
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39 lines
2.0 KiB
HTML
<p>You are given an <code>n x n</code> integer matrix <code>grid</code> where each value <code>grid[i][j]</code> represents the elevation at that point <code>(i, j)</code>.</p>
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<p>The rain starts to fall. At time <code>t</code>, the depth of the water everywhere is <code>t</code>. You can swim from a square to another 4-directionally adjacent square if and only if the elevation of both squares individually are at most <code>t</code>. You can swim infinite distances in zero time. Of course, you must stay within the boundaries of the grid during your swim.</p>
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<p>Return <em>the least time until you can reach the bottom right square </em><code>(n - 1, n - 1)</code><em> if you start at the top left square </em><code>(0, 0)</code>.</p>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/06/29/swim1-grid.jpg" style="width: 164px; height: 165px;" />
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<pre>
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<strong>Input:</strong> grid = [[0,2],[1,3]]
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<strong>Output:</strong> 3
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Explanation:
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At time 0, you are in grid location (0, 0).
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You cannot go anywhere else because 4-directionally adjacent neighbors have a higher elevation than t = 0.
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You cannot reach point (1, 1) until time 3.
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When the depth of water is 3, we can swim anywhere inside the grid.
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</pre>
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<p><strong class="example">Example 2:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/06/29/swim2-grid-1.jpg" style="width: 404px; height: 405px;" />
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<pre>
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<strong>Input:</strong> grid = [[0,1,2,3,4],[24,23,22,21,5],[12,13,14,15,16],[11,17,18,19,20],[10,9,8,7,6]]
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<strong>Output:</strong> 16
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<strong>Explanation:</strong> The final route is shown.
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We need to wait until time 16 so that (0, 0) and (4, 4) are connected.
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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>n == grid.length</code></li>
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<li><code>n == grid[i].length</code></li>
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<li><code>1 <= n <= 50</code></li>
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<li><code>0 <= grid[i][j] < n<sup>2</sup></code></li>
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<li>Each value <code>grid[i][j]</code> is <strong>unique</strong>.</li>
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</ul>
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