SumMultiples.php

<?php

namespace App;

/**
 * Sum Multiples
 *
 * 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.
 *
 * https://leetcode.com/problems/sum-multiples
 */
class SumMultiples
{
    /**
     * @param int $n
     * @return int
     */
    public function sumOfMultiples(int $n): int
    {
        $sum = 0;
        for ($i = 1; $i <= $n; $i++) {
            if ($i % 3 === 0 || $i % 5 === 0 || $i % 7 === 0) {
                $sum += $i;
            }
        }
        return $sum;
    }
}