Find Single Number

Problem : Given an array of integers, every element appears twice except one. Find that single one in linear time. Can you do it in without using extra memory ?
Basic idea is to scan the array you take a xor of each element. Duplicate elements will cancel each other.

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public class Solution { public int singleNumber(int[] nums) { if(nums == null){ return 0; } if(nums.length == 1){ return nums[0]; } int result =0; for(int i=0; i < nums.length; i++){ result = result^nums[i]; } return result; } }