leetcode--Single Number II

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

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

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1. public class Solution {  
2.     public int singleNumber(int[] nums) {  
3.         int len = Integer.SIZE;  
4.         int res = 0;  
5.         int[] arr = new int[len];  
6.         for(int i=0;i<nums.length;i++){  
7.             for(int j=0;j<len;j++){  
8.                 arr[j] += (nums[i]>>j)&1;  
9.                 arr[j] %= 3;  
10.             }  
11.         }  
12.         for(int i=0;i<len;i++){  
13.             res += (arr[i]<<i);  
14.         }  
15.         return res;  
16.     }  
17. } 

原文链接http://blog.youkuaiyun.com/crazy__chen/article/details/46563271