A bit vector is basically just a sequence of bits such as a word or even an
array of words. Here is an example...
int x = 5; // 32 bit word size on Intel IA-32 Architecture In C
programming language.
A variable in C will be either located in a register in memory or in Main
Memory. You can even have bit vector data structures
reside on the hard disk. It just looks like this
10010101010010101.......
If I'm interpreting the solution properly you will index into the bit
vector based on the number found in the array A that is
for j = 1... A.size
currentNumber = A[j] // The jth array element
bitVector[currentNumber] = ~ bitVector[currentNumber] ; // Toggle the
currentNumber bit
end for
Although this is a big memory save, you're still not using constant memory
because the size of your memory is dependent on the size of a word let's
say k
In worst case the space complexity will be 2*2^k = O(2^(K+1))
On Wednesday, April 3, 2013 9:58:23 AM UTC-8, ashekhar007 wrote:
> hi sourab please explain what bit vector1 and bit vector 2 really are can
> you give an example please?
>
> On Saturday, February 16, 2013 11:20:59 PM UTC+5:30, sourabh wrote:
>>
>> you can solve this problem using bitvector/bitset.
>>
>> first scan :
>> scan the array set the bit on odd occurrence and unset on even or
>> 0 occurrence.
>>
>> second scan :
>> shift all the odd occurring elements in beginning of array and even
>> towards end.
>>
>> third scan : till end of odd occurring elements.
>> take another bit vector
>> on first occurence :if bit is set in bv1 then unset it and set it in bv2.
>> on second occurence : if bv1 is not set and bv2 is set then these are the
>> array elements occuring 3rd time.
>>
>>
>>
>>
>>
>> On Wed, Feb 13, 2013 at 9:27 PM, prakhar singh <prakhars...@gmail.com>wrote:
>>
>>> Yes, thats a valid point Don.
>>> Thats what i meant when i wrote "//is that correct?" in the comments on
>>> the array line in code.
>>>
>>>
>>> int a[] = {2,2,3,3,3,1,1,4,4}; // is this correct?
>>>
>>>
>>> On Wed, Feb 13, 2013 at 9:09 PM, Don <dond...@gmail.com> wrote:
>>>
>>>> The xor approach only works if there are no values which occur only
>>>> once. But the problem statement indicates that some numbers occur
>>>> once, some occur twice, and one occurs three times. So you will end up
>>>> with prod equal to the xor of all of the values which occur once or
>>>> three times. Put that in your input array and you'll find that you
>>>> don't get the desired output.
>>>>
>>>> I don't know of a solution better than sorting and scanning the array.
>>>>
>>>> Don
>>>>
>>>> On Feb 12, 3:14 pm, prakhar singh <prakharsngh.1...@gmail.com> wrote:
>>>> > #include<stdio.h>
>>>> >
>>>> > int main()
>>>> > {
>>>> > int a[] = {2,2,3,3,3,1,1,4,4}; // is this correct?
>>>> > int prod=a[0];int i;
>>>> > for(i=1;i<(int)sizeof(a)/sizeof(a[0]);i++)
>>>> > {
>>>> > prod ^= a[i];
>>>> > }
>>>> > printf("%d\n",prod); //outputs 3, algorithm works as Sachin
>>>> described
>>>> > it;
>>>> >
>>>> > }
>>>> >
>>>> > On Tue, Feb 12, 2013 at 11:44 PM, Sachin Chitale
>>>> > <sachinchital...@gmail.com>wrote:
>>>> >
>>>> >
>>>> >
>>>> >
>>>> >
>>>> >
>>>> >
>>>> > > use ex-or operation for all array elements..
>>>> > > a^a=0
>>>> > > a^a^a=a
>>>> >
>>>> > > On Sun, Feb 10, 2013 at 8:22 AM, Mohanabalan D B <
>>>> mohanabala...@gmail.com>wrote:
>>>> >
>>>> > >> can use counting sort
>>>> >
>>>> > >> On Sun, Jul 15, 2012 at 6:37 PM, santosh thota <
>>>> santoshthot...@gmail.com>wrote:
>>>> >
>>>> > >>> If we can retrieve ith prime efficiently, we can do the
>>>> following...
>>>> > >>> 1.maintain a prod=1, start from 1st element, say a[0]=n find n th
>>>> prime
>>>> > >>> 2.check if (prod% (ith_prime * ith_prime )==0) then return i;
>>>> > >>> else prod=prod*ith_prime;
>>>> > >>> 3.repeat it till end
>>>> >
>>>> > >>> On Thursday, 12 July 2012 10:55:02 UTC+5:30, algo bard wrote:
>>>> >
>>>> > >>>> Given an array of integers where some numbers repeat once, some
>>>> numbers
>>>> > >>>> repeat twice and only one number repeats thrice, how do you find
>>>> the number
>>>> > >>>> that gets repeated 3 times?
>>>> >
>>>> > >>>> Does this problem have an O(n) time and O(1) space solution?
>>>> > >>>> No hashmaps please!
>>>> >
>>>> > >>> --
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>>>> > > --
>>>> > > Regards,
>>>> > > Sachin Chitale
>>>> > > Application Engineer SCJP, SCWCD
>>>> > > Contact# : +91 8086284349, 9892159511
>>>> > > Oracle Corporation
>>>> >
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>>> --
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>>>
>>>
>>
>>
>>
>> --
>> Regards,
>> Sourabh Kumar Jain
>> +91-8971547841
>>
>
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