LeetCode-in-Java
2652. Sum Multiples
Easy
Given a positive integer n, find the sum of all integers in the range [1, n] inclusive that are divisible by 3, 5, or 7.
Return an integer denoting the sum of all numbers in the given range satisfying the constraint.
Example 1:
Input: n = 7
Output: 21
Explanation: Numbers in the range [1, 7] that are divisible by 3, 5, or 7 are 3, 5, 6, 7. The sum of these numbers is 21.
Example 2:
Input: n = 10
Output: 40
Explanation: Numbers in the range [1, 10] that are divisible by 3, 5, or 7 are 3, 5, 6, 7, 9, 10. The sum of these numbers is 40.
Example 3:
Input: n = 9
Output: 30
Explanation: Numbers in the range [1, 9] that are divisible by 3, 5, or 7 are 3, 5, 6, 7, 9. The sum of these numbers is 30.
Constraints:
1 <= n <= 103
Solution
public class Solution {
public int sumOfMultiples(int n) {
return sumOfDivisible(n, 3)
+ sumOfDivisible(n, 5)
+ sumOfDivisible(n, 7)
- (sumOfDivisible(n, 15) + sumOfDivisible(n, 35) + sumOfDivisible(n, 21))
+ sumOfDivisible(n, 105);
}
private int sumOfDivisible(int n, int value) {
int high = (n / value) * value;
int count = (high + value - value) / value;
return (value + high) * count / 2;
}
}