yes, on every push/pop there will be max 2 push/pop and 2 comparisons which
is ultimately O(1).
(only in case of 1st element of stack there will be 3 push/pop)

-Regards
Amit Agarwal
blog.amitagrwal.com



On Fri, Oct 8, 2010 at 9:31 AM, saurabh singh <saurabh.n...@gmail.com>wrote:

> yes i too think now that it should work..but on every push/pop we will
> need  to update the other two stacks also which can be done in constant
> time..
>
>
> On Fri, Oct 8, 2010 at 12:58 AM, tech rascal <techrascal...@gmail.com>wrote:
>
>> I think saurabh gupta is rite.....if v take 2 extra stacks ...1 for min
>> and 1 for max, thn some space wud b saved.
>> for the above example .........max_stack wud b-
>>
>> ------------------------>top
>> 45 56 66 76 44343
>>
>> and min_stack wud b-
>>
>> --------------->top
>> 45 22 3 2 -999
>>
>> so, here v need 2 save only 5 elements in max_stack, 5 elements in
>> min_stack and 15 elements in full_stack ( acc 2 above example only), hence
>> total=25 elements..........othrwise if u do it by taking only 1 stack thn u
>> need space for ..15X3 (45)elements.
>>
>> tell me if I am wrong..
>>
>> On Thu, Oct 7, 2010 at 11:49 PM, saurabh singh <saurabh.n...@gmail.com>wrote:
>>
>>> Sorry but I have still not got the solution u have tried to propose here.
>>> Firstly the space complexity remain O(n) only what I said.
>>>
>>> To understand thing u said better lets take an example of stack with
>>> following entries
>>>
>>> --------------------------->top
>>> 45  22  56 44 55 3  2  4 -999 4 2  45 66 76 44343
>>>
>>> how will your second stack look like and how will the push/pop/min/max
>>> will work here ?
>>>
>>>
>>>
>>> On Thu, Oct 7, 2010 at 11:33 PM, Saurabh Gupta <
>>> saurabhgupta1...@gmail.com> wrote:
>>>
>>>>
>>>>
>>>> On Tue, Oct 5, 2010 at 9:47 AM, saurabh singh 
>>>> <saurabh.n...@gmail.com>wrote:
>>>>
>>>>> elaborate plz
>>>>
>>>>
>>>> For every new element in stack, you need thrice of space to store the
>>>> min and max elements also. This has the effect that at state of stack, you
>>>> can get the min and max till that point. Instead of this, maintaining a new
>>>> stack for min elements would be much more efficient in terms of memory 
>>>> since
>>>> in that all the number of elements would be lesser than the main one.
>>>>
>>>> so, basically in your solution, the size of object will be three times
>>>> bigger than the data type which can hold the number otherwise.
>>>>
>>>>
>>>>>
>>>>> On Tue, Oct 5, 2010 at 9:42 AM, Saurabh Gupta <
>>>>> saurabhgupta1...@gmail.com> wrote:
>>>>>
>>>>>> In this method, the extra memory is used. In fact, maintaining a
>>>>>> separate stack of min and max would consume lesser memory than this.
>>>>>>
>>>>>> On Thu, Sep 30, 2010 at 12:17 AM, saurabh singh <
>>>>>> saurabh.n...@gmail.com> wrote:
>>>>>>
>>>>>>> You will just need to see what is min and max available on the
>>>>>>> current top before push. in case of pop u dnt need to do anything...
>>>>>>>
>>>>>>> consider this array imp of stack
>>>>>>> each array index is stored with this object : {data, min_till_here,
>>>>>>> max_till_here}
>>>>>>>
>>>>>>> ------------------------------------------------------------->Top
>>>>>>> [{4,4,4} , {2,2,4}, {7,2,7} , {-6,-6,7}, {1,-6,7}, {9,-6,9}]
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> So if u push say 20 then at top u see whats max and min till now.
>>>>>>> since curr min (-6) is smaller than 20 so min remains unaffected and 
>>>>>>> since
>>>>>>> curr max (9) is smaller than 20 so curr max becomes 20. Hence the 
>>>>>>> object at
>>>>>>> top in stack looks like {20,-6,20}
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Sep 29, 2010 at 10:18 PM, albert theboss <
>>>>>>> alberttheb...@gmail.com> wrote:
>>>>>>>
>>>>>>>>
>>>>>>>> when we pop out something ....
>>>>>>>> we need to find the max min again if max or min is popped out...
>>>>>>>> this ll take again O(n) to find max and min....
>>>>>>>>
>>>>>>>> Correct me if am wrong....
>>>>>>>>
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>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Thanks & Regards,
>>>>>>> Saurabh
>>>>>>>
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>>>>>
>>>>>
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>>>>>
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>>>
>>>
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