2427. Number of Common Factors
Given two positive integers a and b, return the number of common factors of a and b.
An integer x is a common factor of a and b if x divides both a and b.
2428. Maximum Sum of an Hourglass
You are given an m x n integer matrix grid.
We define an hourglass as a part of the matrix with the following form:
Return the maximum sum of the elements of an hourglass.
Note that an hourglass cannot be rotated and must be entirely contained within the matrix.
Given two positive integers num1 and num2, find the integer x such that:
- x has the same number of set bits as num2, and
- The value x XOR num1 is minimal.
Note that XOR is the bitwise XOR operation.
Return the integer x. The test cases are generated such that x is uniquely determined.
The number of set bits of an integer is the number of 1’s in its binary representation.
2430. Maximum Deletions on a String
You are given a string s consisting of only lowercase English letters. In one operation, you can:
- Delete the entire string s, or
- Delete the first i letters of s if the first i letters of s are equal to the following i letters in s, for any i in the range 1 <= i <= s.length / 2.
For example, if s = “ababc”, then in one operation, you could delete the first two letters of s to get “abc”, since the first two letters of s and the following two letters of s are both equal to “ab”.
Return the maximum number of operations needed to delete all of s.
