Package g1201_1300.s1218_longest_arithmetic_subsequence_of_given_difference

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    1218 - Longest Arithmetic Subsequence of Given Difference.

    Medium

    Given an integer array arr and an integer difference, return the length of the longest subsequence in arr which is an arithmetic sequence such that the difference between adjacent elements in the subsequence equals difference.

    A subsequence is a sequence that can be derived from arr by deleting some or no elements without changing the order of the remaining elements.

    Example 1:

    Input: arr = 1,2,3,4, difference = 1

    Output: 4

    Explanation: The longest arithmetic subsequence is 1,2,3,4.

    Example 2:

    Input: arr = 1,3,5,7, difference = 1

    Output: 1

    Explanation: The longest arithmetic subsequence is any single element.

    Example 3:

    Input: arr = 1,5,7,8,5,3,4,2,1, difference = -2

    Output: 4

    Explanation: The longest arithmetic subsequence is 7,5,3,1.

    Constraints:

    • <code>1 <= arr.length <= 10<sup>5</sup></code>

    • <code>-10<sup>4</sup><= arri, difference <= 10<sup>4</sup></code>

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer longestSubsequence(IntArray arr, Integer difference)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait