Single Number

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package cn.edu.xidian.sselab.hashtable; /**  *  * @author zhiyong wang  * title: Single Number  * content:  * Given an 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?  *  *  */ public class SingleNumber {     //利用异或操作，相同为0，相异为1，这样一次循环就能找到不同的那个数     public int singleNumber(int[] nums){         int length = nums.length;         int result = 0;         for(int i=0;i<length;i++){             result = result ^ nums[i];         }         return result;     }          public static void main(String[] args) {         SingleNumber single = new SingleNumber();         System.out.println(single.singleNumber(new int[]{1,2,1}));;     } }