136. Single Number

Given an array of integers, every element appears twice except for one. Find that single one.

public class _136 {    public static void main(String[] args) {        int[] nums = {1,2,3,2,5,99,4,5,99,4,1};        int flag = 0;        for (int i = 0; i < nums.length; i++) {            flag = flag ^ nums[i];        }        System.out.println(flag);    }}