Class Solution
java.lang.Object
g1901_2000.s1901_find_a_peak_element_ii.Solution
1901 - Find a Peak Element II.<p>Medium</p>
<p>A <strong>peak</strong> element in a 2D grid is an element that is <strong>strictly greater</strong> than all of its <strong>adjacent</strong> neighbors to the left, right, top, and bottom.</p>
<p>Given a <strong>0-indexed</strong> <code>m x n</code> matrix <code>mat</code> where <strong>no two adjacent cells are equal</strong> , find <strong>any</strong> peak element <code>mat[i][j]</code> and return <em>the length 2 array</em> <code>[i,j]</code>.</p>
<p>You may assume that the entire matrix is surrounded by an <strong>outer perimeter</strong> with the value <code>-1</code> in each cell.</p>
<p>You must write an algorithm that runs in <code>O(m log(n))</code> or <code>O(n log(m))</code> time.</p>
<p><strong>Example 1:</strong></p>
<p><img src="https://assets.leetcode.com/uploads/2021/06/08/1.png" alt="" /></p>
<p><strong>Input:</strong> mat = [[1,4],[3,2]]</p>
<p><strong>Output:</strong> [0,1]</p>
<p><strong>Explanation:</strong> Both 3 and 4 are peak elements so [1,0] and [0,1] are both acceptable answers.</p>
<p><strong>Example 2:</strong></p>
<p><strong><img src="https://assets.leetcode.com/uploads/2021/06/07/3.png" alt="" /></strong></p>
<p><strong>Input:</strong> mat = [[10,20,15],[21,30,14],[7,16,32]]</p>
<p><strong>Output:</strong> [1,1]</p>
<p><strong>Explanation:</strong> Both 30 and 32 are peak elements so [1,1] and [2,2] are both acceptable answers.</p>
<p><strong>Constraints:</strong></p>
<ul>
<li><code>m == mat.length</code></li>
<li><code>n == mat[i].length</code></li>
<li><code>1 <= m, n <= 500</code></li>
<li><code>1 <= mat[i][j] <= 10<sup>5</sup></code></li>
<li>No two adjacent cells are equal.</li>
</ul>
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Constructor Summary
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Solution
public Solution()
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Method Details
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findPeakGrid
public int[] findPeakGrid(int[][] mat)
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