Find a single occurring element in an array where each element occurred twice.

Given a non-empty array of integers, every element appears twice except for one. Find that single one.

Note:

Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

Example 1:

Input: [2,2,1]

Output: 1

Example 2:

Input: [4,1,2,1,2]

Output: 4

Solution:

using System;
using System.Collections.Generic;
using System.Text;

namespace LeetCode.Easy
{
 class SingleNumberSolution
 {
 public void execute()
 {

 var input = new int[] { 2, 2, 1 };
 int res = SingleNumber(input);
 }

 public int SingleNumber(int[] nums)
 {
 int val = nums[0];
 for (int i = 1; i < nums.Length; i++)
 {
 val = val ^ nums[i];
 } 
 return val;
 }
 }
}

Time Complexity: O(n)

Space Complexity: O(1)