Sure, if only one number is missing and all the other numbers are distinct. And we know those numbers are from 1 to n. First we xor all the numbers, we get xor1, then we let xor1 xor with numbers from 1 to n. Since xor means 1 xor 1=0, then all the number appear in the file will null out (those bits are set to 0). The bits left that are 1 in xor1 must be the missing number.Noted that this method has three assumptions
On Thu, Jun 23, 2011 at 9:21 AM, Sriganesh Krishnan <[email protected]>wrote: > can you explain me....what the logic is...behind the xor operation?...is it > like inversion or encryption? > > On Thu, Jun 23, 2011 at 11:59 AM, sunny agrawal > <[email protected]>wrote: > >> initially compute xor of all the values from 0 to n in a variable Temp >> so temp = 0^1^2........^n >> let result is used to store the missing number >> for each ith bit of missing number where i = 0-31 we can find it as >> following >> ith bit of result = (xor of all ith bits of values of array) xored with >> (ith >> bit of temp) >> >> On Thu, Jun 23, 2011 at 12:25 AM, oppilas . <[email protected]>wrote: >> >>> Is the array sorted? >>> In A[1..n], one number is missing from 0 to N. So, >>> A[5]={--INF, 2,1,3,0} is a valid case? >>> >>> >>> On Wed, Jun 22, 2011 at 11:51 PM, RollBack <[email protected]> wrote: >>> >>>> An array A[1...n] contains all the integers from 0 to n except for one >>>> number which is >>>> missing. In this problem, we cannot access an entire integer in A with >>>> a single opera- >>>> tion. The elements of A are represented in binary, and the only >>>> operation we can use >>>> to access them is “fetch the jth bit of A[i]”, which takes constant >>>> time. Write code to >>>> find the missing integer. Can you do it in O(n) time? >>>> _ >>>> _ _____________________________________________ >>>> >>>> Rajeev N Bharshetty >>>> I Blog @ www.opensourcemania.co.cc >>>> >>>> -- >>>> 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 >>>> [email protected]. >>>> For more options, visit this group at >>>> http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> >>> -- >>> 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 >>> [email protected]. >>> For more options, visit this group at >>> http://groups.google.com/group/algogeeks?hl=en. >>> >> >> >> >> -- >> Sunny Aggrawal >> B-Tech IV year,CSI >> Indian Institute Of Technology,Roorkee >> >> -- >> 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 >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/algogeeks?hl=en. >> > > -- > 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 > [email protected]. > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- 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 [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
