Company-Wise Interview Questions

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:

Hint 1

Fix the value of <code>(subs[0] + subs[1]) % k</code> from the <code>k</code> possible values. Let it be <code>val</code>.

Hint 2

Let <code>dp[i]</code> store the maximum length of a subsequence with its last element <code>x</code> such that <code>x % k == i</code>.

Hint 3

Answer for a subsequence ending at index <code>y</code> is <code>dp[(k + val - (y % k)) % k] + 1</code>.

Acceptance

57.3%

Submissions

176,868

Accepted

101,277

3491. Find the Maximum Length of Valid Subsequence II