136. Single Number

// LeetCode URL: https://leetcode.com/problems/single-number/

/**
 * XOR of all numbers. XOR result is the answer.
 *
 * Time Complexity: O(N)
 *
 * Space Complexity: O(1)
 *
 * N = Length of the input array.
 */
class Solution {
    public int singleNumber(int[] nums) throws IllegalArgumentException {
        if (nums == null || nums.length == 0) {
            throw new IllegalArgumentException("Invalid Input");
        }

        int result = 0;

        for (int num : nums) {
            result ^= num;
        }

        return result;
    }
}