3215. Count Triplets with Even XOR Set Bits II

Given three integer arrays a, b, and c, return the number of triplets (a[i], b[j], c[k]), such that the bitwise XOR between the elements of each triplet has an even number of set bits.

3744. Find Kth Character in Expanded String

You are given a string s consisting of one or more words separated by single spaces. Each word in s consists of lowercase English letters.

We obtain the expanded string t from s as follows:

• For each word in s, repeat its first character once, then its second character twice, and so on.

For example, if s = "hello world", then t = "heelllllllooooo woorrrllllddddd".

You are also given an integer k, representing a valid index of the string t.

Return the kth character of the string t.

3647. Maximum Weight in Two Bags

You are given an integer array weights and two integers w1 and w2 representing the maximum capacities of two bags.

Each item may be placed in at most one bag such that:

• Bag 1 holds at most w1 total weight.
• Bag 2 holds at most w2 total weight.

Return the maximum total weight that can be packed into the two bags.

3610. Minimum Number of Primes to Sum to Target

You are given two integers n and m.

You have to select a multiset of prime numbers from the first m prime numbers such that the sum of the selected primes is exactly n. You may use each prime number multiple times.

Return the minimum number of prime numbers needed to sum up to n, or -1 if it is not possible.

3253. Construct String with Minimum Cost (Easy)

You are given a string target, an array of strings words, and an integer array costs, both arrays of the same length.

Imagine an empty string s.

You can perform the following operation any number of times (including zero):

• Choose an index i in the range [0, words.length - 1].
• Append words[i] to s.
• The cost of operation is costs[i].

Return the minimum cost to make s equal to target. If it’s not possible, return -1.

3460. Longest Common Prefix After at Most One Removal

You are given two strings s and t.

Return the length of the longest common prefix between s and t after removing at most one character from s.

Note: s can be left without any removal.

3221. Maximum Array Hopping Score II

Given an array nums, you have to get the maximum score starting from index 0 and hopping until you reach the last element of the array.

In each hop, you can jump from index i to an index j > i, and you get a score of (j - i) * nums[j].

Return the maximum score you can get.

3672. Sum of Weighted Modes in Subarrays

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

For every subarray of length k:

• The mode is defined as the element with the highest frequency. If there are multiple choices for a mode, the smallest such element is taken.
• The weight is defined as mode * frequency(mode).

Return the sum of the weights of all subarrays of length k.

Note:

• A subarray is a contiguous non-empty sequence of elements within an array.
• The frequency of an element x is the number of times it occurs in the array.

3466. Maximum Coin Collection

Mario drives on a two-lane freeway with coins every mile. You are given two integer arrays, lane1 and lane2, where the value at the ith index represents the number of coins he gains or loses in the ith mile in that lane.

• If Mario is in lane 1 at mile i and lane1[i] > 0, Mario gains lane1[i] coins.
• If Mario is in lane 1 at mile i and lane1[i] < 0, Mario pays a toll and loses abs(lane1[i]) coins.
• The same rules apply for lane2.

Mario can enter the freeway anywhere and exit anytime after traveling at least one mile. Mario always enters the freeway on lane 1 but can switch lanes at most 2 times.

A lane switch is when Mario goes from lane 1 to lane 2 or vice versa.

Return the maximum number of coins Mario can earn after performing at most 2 lane switches.

Note: Mario can switch lanes immediately upon entering or just before exiting the freeway.

3496. Maximize Score After Pair Deletions

You are given an array of integers nums. You must repeatedly perform one of the following operations while the array has more than two elements:

• Remove the first two elements.
• Remove the last two elements.
• Remove the first and last element.

For each operation, add the sum of the removed elements to your total score.

Return the maximum possible score you can achieve.