// 2894. Divisible and Non-divisible Sums Difference #include "leetcode.h" /* * you are given a positive integers 'n' and 'm'. define two integers as * follows: 'num1': the sum of all integers in the range '[1, n]' that are not * divisible by 'm'. 'num2': the sum of all integers in the range '[1, n]' that * are divisible by 'm'. return the integer 'num1 - num2' */ int differenceOfSums(int n, int m) { return (1 + n) * n / 2 - (1 + n / m) * (n / m) * m; } int main() { printf("%d\n", differenceOfSums(10, 3)); // expect: 19 printf("%d\n", differenceOfSums(5, 6)); // expect: 15 printf("%d\n", differenceOfSums(5, 1)); // expect: -15 }