Q2 o(1) space o(n) sol.
traverse through the array.
do -1*a[abs(a[i])-1] if a[abs(a[i])-1) +ve else do nothing
traverse again to check for the indexes with +ve values.
On Wed, Jul 20, 2011 at 1:01 PM, Shubham Maheshwari <
shubham.veloc...@gmail.com> wrote:
> let A:: ((n(n+1)/2) - sum)
> let B:: ((n(n+1)(2n+1)/6) - (sum of squares of elements))
>
> then missing number = ((B/A) + A)/2;
>
> complexity O(n).
> space complexity O(1).
>
> On Wed, Jul 20, 2011 at 12:47 PM, saurabh singh <saurab...@gmail.com>wrote:
>
>> Q1 can be solved using some simple maths....:)
>> Hint:What is the sum of first n natural numbers?"And what is the sum of
>> squares of first n natural numbers?
>>
>>
>> On Wed, Jul 20, 2011 at 12:44 PM, siva viknesh <sivavikne...@gmail.com>wrote:
>>
>>> gn array - say a
>>>
>>> hav extra array - say b - initialise all values to zero
>>>
>>> ques 1:
>>>
>>> for(i=1;i<=n;i++)
>>> {
>>> b[a[i]]++;
>>>
>>> }
>>>
>>> then traverse b array and print i, for which b[i] = 2
>>>
>>> o(n) time & space
>>>
>>> same idea for ques 2
>>>
>>> ....better approaches please
>>>
>>> On Jul 20, 12:11 pm, siva viknesh <sivavikne...@gmail.com> wrote:
>>> > gn array - say a
>>> >
>>> > hav extra array - say b - initialise all values to zero
>>> >
>>> > ques 1:for(i=1;i<=n;i++)
>>> > {
>>> > b[a[i]]++;
>>> >
>>> > }
>>> >
>>> > On Jul 20, 12:07 pm, siva viknesh <sivavikne...@gmail.com> wrote:
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > > 1.Given an array of size n. It contains numbers in the range 1 to n.
>>> > > Each number is present at least once except for 2 numbers. Find the
>>> > > missing numbers.
>>> >
>>> > > 2.Given an array of size n. It contains numbers in the range 1 to n.
>>> > > Find the numbers which aren’t present.
>>>
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>>
>>
>> --
>> Saurabh Singh
>> B.Tech (Computer Science)
>> MNNIT ALLAHABAD
>>
>>
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>
>
>
> --
> Shubham Maheshwari
> ShubZz
> O.o o.O
>
> enJoY ...!!!
>
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--
Saurabh Singh
B.Tech (Computer Science)
MNNIT ALLAHABAD
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