2370. Longest Ideal Subsequence
You are given a string s consisting of lowercase letters and an integer k. We call a string t ideal if the following conditions are satisfied:
- t is a subsequence of the string s.
- The absolute difference in the alphabet order of every two adjacent letters in t is less than or equal to k.
Return the length of the longest ideal string.
A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.
Note that the alphabet order is not cyclic. For example, the absolute difference in the alphabet order of ‘a’ and ‘z’ is 25, not 1.
2369. Check if There is a Valid Partition For The Array
You are given a 0-indexed integer array nums. You have to partition the array into one or more contiguous subarrays.
We call a partition of the array valid if each of the obtained subarrays satisfies one of the following conditions:
- The subarray consists of exactly 2 equal elements. For example, the subarray [2,2] is good.
- The subarray consists of exactly 3 equal elements. For example, the subarray [4,4,4] is good.
- The subarray consists of exactly 3 consecutive increasing elements, that is, the difference between adjacent elements is 1. For example, the subarray [3,4,5] is good, but the subarray [1,3,5] is not.
Return true if the array has at least one valid partition. Otherwise, return false.
2368. Reachable Nodes With Restrictions
There is an undirected tree with n nodes labeled from 0 to n - 1 and n - 1 edges.
You are given a 2D integer array edges of length n - 1 where edges[i] = [ai, bi] indicates that there is an edge between nodes ai and bi in the tree. You are also given an integer array restricted which represents restricted nodes.
Return the maximum number of nodes you can reach from node 0 without visiting a restricted node.
Note that node 0 will not be a restricted node.
2367. Number of Arithmetic Triplets
You are given a 0-indexed, strictly increasing integer array nums and a positive integer diff. A triplet (i, j, k) is an arithmetic triplet if the following conditions are met:
- i < j < k,
- nums[j] - nums[i] == diff, and
- nums[k] - nums[j] == diff.
Return the number of unique arithmetic triplets.