LeetCode-Single Number II

Posted petewell

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了LeetCode-Single Number II相关的知识，希望对你有一定的参考价值。

LeetCode地址：https://leetcode.com/problems/single-number-ii/

Problem:
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?

思路

  • 将数组A中每个整形的二进制 分散到一个32位数组A上求和，出现3次的在该位上的和肯定是3的倍数
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
 
public class  
    public int singleNumber(int[] A) 
        int ret=0,index=0;
        int[] binarySum=new int[32];
        if(A==null || A.length==0)
            return ret;
        
        for(int i=0;i<A.length;i++)
        
            index=0;
            do
            
                binarySum[index++]+=A[i]%2;
                A[i]/=2;
            while(A[i]!=0);
        
        
        
        for(int i=0;i<binarySum.length;i++)
        
            index=binarySum[i]%3;
            if(Math.abs(index)>1)
            
                index=(index+3)%3;
            
            ret+=Math.pow(2, i)*(index);
        
        
        return ret;

原文:大专栏  LeetCode-Single Number II


以上是关于LeetCode-Single Number II的主要内容，如果未能解决你的问题，请参考以下文章

leetcode-Single Number II-137

leetcode-Single Number III-260

Single Number II

137. Single Number II

137. Single Number II

LeetcodeUgly Number II