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?

 

 

求出数组中只出现一次的数，剩下的都是三次。

 

 

/**
 * Created by wangzunwen on 2016/11/14.
 */
public class singleNumber2 {

    public int singleNumber(int[] nums) {


        int result = 0;

        for( int i = 0;i<32;i++){

            int num = 0;
            for( int j = 0;j<nums.length;j++){
                if(( nums[j] >> i &1) == 1 ){
                    num++;
                } 


            }
            num%=3;
            result+=(num<<i);
        }
        return result;


    }
}

 

 

public class Solution {
    public int singleNumber(int[] A) {
        int n = A.length;
        int one=0, two=0, three=0;  
        for(int i=0; i<n; i++){  
            two |= one&A[i];  
            one^=A[i];  
            //cout<<one<<endl;  
            three=one&two;  
            one&= ~three;  
            two&= ~three;  
        }  
        return one; 

    }
}