3202: Find the Maximum Length of Valid Subsequence II

Problem Statement

You are given an integer array nums and a positive integer k.

A subsequence sub of nums with length x is called valid if it satisfies:

  • (sub[0] + sub[1]) % k == (sub[1] + sub[2]) % k == ... == (sub[x - 2] + sub[x - 1]) % k.
Return the length of the longest valid subsequence of nums.

Example 1:

Input: nums = [1,2,3,4,5], k = 2

Output: 5

Explanation:

The longest valid subsequence is [1, 2, 3, 4, 5].

Example 2:

Input: nums = [1,4,2,3,1,4], k = 3

Output: 4

Explanation:

The longest valid subsequence is [1, 4, 1, 4].

Constraints:

  • 2 <= nums.length <= 103
  • 1 <= nums[i] <= 107
  • 1 <= k <= 103

Code Solution