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 = 7Output:21Explanation: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 = 10Output:40Explanation: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 = 9Output:30Explanation: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 <= 10`

^{3}

**Solution: Mod**

Time complexity: O(n)

Space complexity: O(1)

## C++

1 2 3 4 5 6 7 8 9 10 11 12 |
// Author: Huahua class Solution { public: int sumOfMultiples(int n) { int ans = 0; for (int i = 1; i <= n; ++i) { if (i % 3 == 0 || i % 5 == 0 || i % 7 == 0) ans += i; } return ans; } }; |