Single number II

Single number II

Problem:

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

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

Ideas:

Hashtable easy to think of

A new idea of bit vector

Others code:

 Public classSolution { Public intSinglenumber (int[] A) {/*element in A was 32bit, sum corresponding bits from all elements and mod 3 then should left the Single Number*/        int[] sum=New int[32]; intRes=0;  for(inti=0;i<32;i++)        {             for(intj=0;j<a.length;j++) {Sum[i]+ = ((a[j]>>i) &1);//sum every bit of all numbers} Sum[i]%=3; Res+ = ((sum[i]&1) <<i);//recover The single number        }        returnRes; }}

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The Learning Place:

• This data structure of bit vectors is fantastic.
• Shift right twice times left shift add 0 increase twice times deep left and right shift meanings
• Transformation and recovery method of data

Single number II