mirror of
https://gitee.com/coder-xiaomo/leetcode-problemset
synced 2025-11-04 03:33:12 +08:00
36 lines
1.3 KiB
HTML
36 lines
1.3 KiB
HTML
<p>Given an integer array <code>arr</code> and an integer <code>difference</code>, return the length of the longest subsequence in <code>arr</code> which is an arithmetic sequence such that the difference between adjacent elements in the subsequence equals <code>difference</code>.</p>
|
|
|
|
<p>A <strong>subsequence</strong> is a sequence that can be derived from <code>arr</code> by deleting some or no elements without changing the order of the remaining elements.</p>
|
|
|
|
<p> </p>
|
|
<p><strong>Example 1:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong> arr = [1,2,3,4], difference = 1
|
|
<strong>Output:</strong> 4
|
|
<strong>Explanation: </strong>The longest arithmetic subsequence is [1,2,3,4].</pre>
|
|
|
|
<p><strong>Example 2:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong> arr = [1,3,5,7], difference = 1
|
|
<strong>Output:</strong> 1
|
|
<strong>Explanation: </strong>The longest arithmetic subsequence is any single element.
|
|
</pre>
|
|
|
|
<p><strong>Example 3:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong> arr = [1,5,7,8,5,3,4,2,1], difference = -2
|
|
<strong>Output:</strong> 4
|
|
<strong>Explanation: </strong>The longest arithmetic subsequence is [7,5,3,1].
|
|
</pre>
|
|
|
|
<p> </p>
|
|
<p><strong>Constraints:</strong></p>
|
|
|
|
<ul>
|
|
<li><code>1 <= arr.length <= 10<sup>5</sup></code></li>
|
|
<li><code>-10<sup>4</sup> <= arr[i], difference <= 10<sup>4</sup></code></li>
|
|
</ul>
|