suppose numbers are 11,12,13,15 then you get some xor_val for xor of all
these numbers
after this

for (int i=11;i<=15;i++) xor_val ^=i;

now xor_val is 14



Best Regards
Ashish Goel
"Think positive and find fuel in failure"
+919985813081
+919966006652


On Sun, Jun 12, 2011 at 9:24 PM, Supraja Jayakumar <[email protected]
> wrote:

> Hi
>
> But does this work on bigger numbers ?
>
> I mean with [11-15] say 14 is missing.
>
> It is:
>
> 1011
> 1100
> 1101
> 1111
> --------
> 0101
> -------
> which is 5 ?
>
> Supraja J
>
>
> On Sat, Jun 11, 2011 at 8:14 AM, Wladimir Tavares 
> <[email protected]>wrote:
>
>> You can use the same idea:
>>
>> Suppose you want to find out what the missing number in the list [1 .. 5]
>> :
>>       1 = 001
>>       2 = 010
>>       3 = 011
>>       4 = 100
>>       5 = 101
>> XOR = 001
>>
>> If the number 4 is missing:
>>   XOR = 001
>>       1 = 001
>>       2 = 010
>>       3 =
>> 011
>>       4 = 100
>>        5 = 101
>>       3 = 011
>> XOR = 011
>>
>>
>> Wladimir Araujo Tavares
>> *Federal University of Ceará
>>
>> *
>>
>>
>>
>>
>> On Thu, Jun 9, 2011 at 8:34 AM, Ashim Kapoor <[email protected]>wrote:
>>
>>> Could someone illustrate the XOR for question 2. I am a beginner to this.
>>>
>>> Many thanks!
>>>
>>>
>>> On Thu, Jun 9, 2011 at 4:58 PM, Piyush Sinha 
>>> <[email protected]>wrote:
>>>
>>>> Xoring it twice ...once with the elements in the file and then from i=1
>>>> to 4,000,000,000..the answer left is the missing number
>>>>
>>>> On Thu, Jun 9, 2011 at 4:46 PM, Dumanshu <[email protected]> wrote:
>>>>
>>>>> I dont think numbers are sorted in the 1st question. btw
>>>>> @sunny: how will xor-ing give the ans? for 1st ques?
>>>>>
>>>>>
>>>>> On Jun 9, 3:34 pm, sunny agrawal <[email protected]> wrote:
>>>>> > yes, but using xor no need of ULL :)
>>>>> >
>>>>> > 2011/6/9 • » νιρυℓ « • <[email protected]>
>>>>>
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> > > Sum wont overflow, ULL range will include sum.
>>>>> >
>>>>> > > On Thu, Jun 9, 2011 at 3:52 PM, sunny agrawal <
>>>>> [email protected]>wrote:
>>>>>
>>>>> >
>>>>> > >> sum can overflow....
>>>>> > >> Xor method can also be applied to Q1. no need of numbers to be
>>>>> sorted.
>>>>> >
>>>>> > >> 2011/6/9 • » νιρυℓ « • <[email protected]>
>>>>>
>>>>> >
>>>>> > >>> For 1.
>>>>> > >>> sum the numbers in the file, subtract it from sum of first 4
>>>>> billion
>>>>> > >>> numbers.
>>>>> >
>>>>> > >>> On Thu, Jun 9, 2011 at 3:44 PM, Navneet Gupta <
>>>>> [email protected]>wrote:
>>>>>
>>>>> >
>>>>> > >>>> The answer to second question is simple. XORing all the elements
>>>>> > >>>> should do it for you.
>>>>> >
>>>>>  > >>>> On Thu, Jun 9, 2011 at 3:15 PM, Dumanshu <[email protected]>
>>>>> wrote:
>>>>> > >>>> > Q1. I  have a file in which there are supposed to be 4 billion
>>>>> > >>>> > numbers,
>>>>> > >>>> > starting from 1 to 4,000,000,000 but unfortunately one number
>>>>> is
>>>>> > >>>> > missing,
>>>>> > >>>> > i.e there are only 3,999,999,999 numbers, I need to find the
>>>>> missing
>>>>> > >>>> > number.
>>>>> >
>>>>> > >>>> > Q2.  I have an array consisting of 2n+1 elements. n elements
>>>>> in it are
>>>>> > >>>> > married, i.e they occur twice in the array, however there is
>>>>> one
>>>>> > >>>> > element
>>>>> > >>>> > which only appears once in the array. I need to find that
>>>>> number in a
>>>>> > >>>> > single pass using constant memory. {assume all are positive
>>>>> numbers}
>>>>> > >>>> > Eg :- 3 4 1 3 1 7 2 2 4
>>>>> > >>>> > Ans:- 7
>>>>> >
>>>>> > >>>> > --
>>>>> > >>>> > You received this message because you are subscribed to the
>>>>> Google
>>>>> > >>>> Groups "Algorithm Geeks" group.
>>>>> > >>>> > To post to this group, send email to
>>>>> [email protected].
>>>>> > >>>> > To unsubscribe from this group, send email to
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>>>>> > >>>> > For more options, visit this group at
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>>>>> >
>>>>> > >>>> --
>>>>> > >>>> --Navneet
>>>>> >
>>>>> > >>>> --
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>>>>> > >>> --
>>>>> > >>> Regards,
>>>>> > >>> Vipul
>>>>> >
>>>>> > >>>  --
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>>>>> > >> --
>>>>> > >> Sunny Aggrawal
>>>>> > >> B-Tech IV year,CSI
>>>>> > >> Indian Institute Of Technology,Roorkee
>>>>> >
>>>>> > >>  --
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>>>>> > > --
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>>>>> > > Vipul
>>>>> >
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>>>>> >
>>>>> > --
>>>>> > Sunny Aggrawal
>>>>> > B-Tech IV year,CSI
>>>>> > Indian Institute Of Technology,Roorkee
>>>>>
>>>>> --
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>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> *Piyush Sinha*
>>>> *IIIT, Allahabad*
>>>> *+91-8792136657*
>>>> *+91-7483122727*
>>>> *https://www.facebook.com/profile.php?id=100000655377926 *
>>>>
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