3882. Minimum XOR Path in a Grid

You are given a 2D integer array grid of size m * n.

You start at the top-left cell (0, 0) and want to reach the bottom-right cell (m - 1, n - 1).

At each step, you may move either right or down.

The cost of a path is defined as the bitwise XOR of all the values in the cells along that path, including the start and end cells.

Return the minimum possible XOR value among all valid paths from (0, 0) to (m - 1, n - 1).

3884. First Matching Character From Both Ends

You are given a string s of length n consisting of lowercase English letters.

Return the smallest index i such that s[i] == s[n - i - 1].

If no such index exists, return -1.

3885. Design Event Manager

You are given an initial list of events, where each event has a unique eventId and a priority.

Implement the EventManager class:

• EventManager(int[][] events) Initializes the manager with the given events, where events[i] = [eventId_i, priority_​​​​​​​i].
• void updatePriority(int eventId, int newPriority) Updates the priority of the active event with id eventId to newPriority.
• int pollHighest() Removes and returns the eventId of the active event with the highest priority. If multiple active events have the same priority, return the smallest eventId among them. If there are no active events, return -1.

An event is called active if it has not been removed by pollHighest().

3887. Incremental Even-Weighted Cycle Queries

You are given a positive integer n.

There is an undirected graph with n nodes labeled from 0 to n - 1. Initially, the graph has no edges.

You are also given a 2D integer array edges, where edges[i] = [u_i, v_i, w_i] represents an edge between nodes u_i and v_i with weight w_i. The weight w_i is either 0 or 1.

Process the edges in edges in the given order. For each edge, add it to the graph only if, after adding it, the sum of the weights of the edges in every cycle in the resulting graph is even.

Return an integer denoting the number of edges that are successfully added to the graph.

3889. Mirror Frequency Distance

You are given a string s consisting of lowercase English letters and digits.

For each character, its mirror character is defined by reversing the order of its character set:

• For letters, the mirror of a character is the letter at the same position from the end of the alphabet.
  • For example, the mirror of 'a' is 'z', and the mirror of 'b' is 'y', and so on.
• For digits, the mirror of a character is the digit at the same position from the end of the range '0' to '9'.
  • For example, the mirror of '0' is '9', and the mirror of '1' is '8', and so on.

For each unique character c in the string:

• Let m be its mirror character.
• Let freq(x) denote the number of times character x appears in the string.
• Compute the absolute difference between their frequencies, defined as: |freq(c) - freq(m)|

The mirror pairs (c, m) and (m, c) are the same and must be counted only once.

Return an integer denoting the total sum of these values over all such distinct mirror pairs.

3886. Sum of Sortable Integers

You are given an integer array nums of length n.

An integer k is called sortable if k divides n and you can sort nums in non-decreasing order by sequentially performing the following operations:

• Partition nums into consecutive subarrays of length k.
• Cyclically rotate each subarray independently any number of times to the left or to the right.

Return an integer denoting the sum of all possible sortable integers k.

3899. Angles of a Triangle

You are given a positive integer array sides of length 3.

Determine if there exists a triangle with positive area whose three side lengths are given by the elements of sides.

If such a triangle exists, return an array of three floating-point numbers representing its internal angles (in degrees), sorted in non-decreasing order. Otherwise, return an empty array.

Answers within 10^-5 of the actual answer will be accepted.

3901. Good Subsequence Queries

You are given an integer array nums of length n and an integer p.

A non-empty subsequence of nums is called good if:

• Its length is strictly less than n.
• The greatest common divisor (GCD) of its elements is exactly p.

You are also given a 2D integer array queries of length q, where each queries[i] = [ind_i, val_i] indicates that you should update nums[ind_i] to val_i.

After each query, determine whether there exists any good subsequence in the current array.

Return the number of queries for which a good subsequence exists.

gcd(a, b)

greatest common divisor

a

b

3900. Longest Balanced Substring After One Swap

You are given a binary string s consisting only of characters '0' and '1'.

A string is balanced if it contains an equal number of '0's and '1's.

You can perform at most one swap between any two characters in s. Then, you select a balanced substring from s.

Return an integer representing the maximum length of the balanced substring you can select.

3903. Smallest Stable Index I

You are given an integer array nums of length n and an integer k.

For each index i, define its instability score as max(nums[0..i]) - min(nums[i..n - 1]).

In other words:

• max(nums[0..i]) is the largest value among the elements from index 0 to index i.
• min(nums[i..n - 1]) is the smallest value among the elements from index i to index n - 1.

An index i is called stable if its instability score is less than or equal to k.

Return the smallest stable index. If no such index exists, return -1.