XOROperationInArray.php

<?php

namespace App;

/**
 * XOR Operation in an Array
 *
 * You are given an integer n and an integer start. Define an array nums where nums[i] = start + 2 * i (0-indexed)
 * and n == nums.length. Return the bitwise XOR of all elements of nums.
 *
 * Example 1:
 * Input: n = 5, start = 0
 * Output: 8
 * Explanation: Array nums is equal to [0, 2, 4, 6, 8] where (0 ^ 2 ^ 4 ^ 6 ^ 8) = 8.
 * Where "^" corresponds to bitwise XOR operator.
 *
 * Example 2:
 * Input: n = 4, start = 3
 * Output: 8
 * Explanation: Array nums is equal to [3, 5, 7, 9] where (3 ^ 5 ^ 7 ^ 9) = 8.
 *
 * https://leetcode.com/problems/xor-operation-in-an-array
 */
class XOROperationInArray
{
    /**
     * @param int $n
     * @param int $start
     * @return int
     */
    public function xorOperation(int $n, int $start): int
    {
        $result = 0;
        for ($i = 0; $i < $n; $i++) {
            $result ^= $start + 2 * $i;
        }
        return $result;
    }
}