Divisible and Non-divisible Sums Difference — LeetCode 2894 Python Solution

The problem

You are given positive integers n and m. Define two integers as follows: num1: The sum of all integers in the range [1, n] (both inclusive) that are not divisible by m.

Example

Input

n = 10, m = 3

Output

19

Explanation

In the given example:

Python solution

class Solution:
    def differenceOfSums(self, n: int, m: int) -> int:
        return sum(i if i % m else -i for i in range(1, n + 1))

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 2894. Divisible and Non-divisible Sums Difference is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Math.

The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.

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