@Shravan: Memory is cheep. $15 or less per gigabyte. When we are
talking about O(n), that allows n to get pretty large cheaply.
Dave
On Sep 5, 10:50 am, Shravan Kumar <shrava...@gmail.com> wrote:
> @Dave agreed
> @Sandeep it works, but it takes more memory
>
> On Mon, Sep 5, 2011 at 9:15 PM, SANDEEP CHUGH <sandeep.aa...@gmail.com>wrote:
>
>
>
> > @dave : ya ryt..
> > @shravan ; my solution works for the case that dave has told.. so at every
> > step we hav to push min..
>
> > On Mon, Sep 5, 2011 at 9:11 PM, Dave <dave_and_da...@juno.com> wrote:
>
> >> @Shravan: You at least have to push equal mins on the min stack.
> >> Otherwise, with the sequence 2, 1, 1, if you push only 2 and 1 onto
> >> the min stack, then when you pop the first 1 from the data stack and
> >> pop the 1 from the min stack, the top of the min stack is 2, but the
> >> minimum in the data stack is 1. So you push 2, 1, 1 onto the min
> >> stack. When you pop the first 1 from the data stack, you pop the first
> >> 1 from the min stack, and still show the min = 1.
>
> >> Don's solution for data sequence 2, 3, 1, 1 would push (2,2) (3,2),
> >> (1,1), (1,1) onto one stack, whereas you should push 2, 3, 1, 1 onto
> >> the data stack and 2, 1, 1 onto the min stack, for a saving of one
> >> stack item. For the sequence 1, 1, 1, 1, 1, 1, 1, you both would have
> >> the same number of items stacked.
>
> >> Dave
>
> >> On Sep 5, 10:09 am, Shravan Kumar <shrava...@gmail.com> wrote:
> >> > @sandeep
>
> >> > You don't need to store duplicate elements in stack2. When you want min
> >> > return top element. When an element is popped from stack1, pop stack2
> >> only
> >> > if it is equal to popped stack1 element.
>
> >> > On Mon, Sep 5, 2011 at 8:21 PM, SANDEEP CHUGH <sandeep.aa...@gmail.com
> >> >wrote:
>
> >> > > In my earlier approach , if the element that is stored in "min" got
> >> popped
> >> > > out then we have to search entire stack for min.. so i think my
> >> earlier
> >> > > approach will not work.. tell me about that??
>
> >> > > and i hav another approach.. also tell me about that also?
>
> >> > > consider we have to push the elemnts 12 , 3, 15 ,8 ,2, 9
>
> >> > > stack 1 stack 2
>
> >> > > 12
>
> >> > > 12
>
> >> > > first 12 came , push in both
>
> >> > > 3
>
> >> > > 12
>
> >> > > 3
>
> >> > > 12
>
> >> > > next 3 came , push 3 in first stack , and
>
> >> > > push minumum ( stack1 top elem , stack2 top elem ) into
> >> stack2
> >> > > .. i.e 3 pushed to 2nd stack
>
> >> > > 15
>
> >> > > 3
>
> >> > > 12
>
> >> > > 3
>
> >> > > 3
>
> >> > > 12
>
> >> > > now for all the numbers that are coming ,
> >> push
> >> > > them into first stack and push min of both stacks top elements into
> >> 2nd
> >> > > stack min (15 , 3) --> 3 pushed to stack2
>
> >> > > 8
>
> >> > > 15
>
> >> > > 3
>
> >> > > 12
>
> >> > > 3
>
> >> > > 3
>
> >> > > 3
>
> >> > > 12
>
> >> > > min (8,3) ---> 3 pushed to stack2
>
> >> > > 2
>
> >> > > 8
>
> >> > > 15
>
> >> > > 3
>
> >> > > 12
>
> >> > > 2
>
> >> > > 3
>
> >> > > 3
>
> >> > > 3
>
> >> > > 12
>
> >> > > min(2,3) --> 2 pushed to stack2
>
> >> > > 9
>
> >> > > 2
>
> >> > > 8
>
> >> > > 15
>
> >> > > 3
>
> >> > > 12
>
> >> > > 2
>
> >> > > 2
>
> >> > > 3
>
> >> > > 3
>
> >> > > 3
>
> >> > > 12
>
> >> > > min(9,2) -- > 2 pushed to stack2
>
> >> > > so if at any time we want to print the minimum element , print the
> >> stack2
> >> > > top element ,
>
> >> > > and if pop() is performed on stack1 , then perform pop() operation on
> >> > > stack2 also .
>
> >> > > after pop () on stack2 , stack2 top still contains the minimum
> >> element for
> >> > > the rest of elements ..
>
> >> > > On Mon, Sep 5, 2011 at 5:15 PM, kARTHIK R <k4rth...@gmail.com> wrote:
>
> >> > >> +1 Don. Good Solution. We can't save space and time at the same time.
> >> > >> Either use extra space and do operations fast, or use O(1) for min,
> >> and if
> >> > >> min is popped, spend O(n) to spot the next min. Depends on the use
> >> case.
>
> >> > >> Karthik R,
> >> > >> R&D Engineer,
> >> > >> Tejas Networks.
>
> >> > >> On Mon, Sep 5, 2011 at 5:10 PM, bharatkumar bagana <
> >> > >> bagana.bharatku...@gmail.com> wrote:
>
> >> > >>> +1 sandeep
> >> > >>> @don: u'r sol is correct , but if the number of elements are very
> >> huge
> >> > >>> and the updated min is long numbers , then we are storing the min in
> >> each
> >> > >>> element ... its waste of memory ...
> >> > >>> if the # elements are less, then this is good sol..
>
> >> > >>> On Mon, Sep 5, 2011 at 1:02 AM, Nitin Garg <
> >> nitin.garg.i...@gmail.com>wrote:
>
> >> > >>>> Don's solution is correct.
> >> > >>>> At each push() operation, you update the value of min element upto
> >> that
> >> > >>>> depth in stack.
> >> > >>>> Can be illustrated with the following example -
>
> >> > >>>> stack = {}
> >> > >>>> push(2) stack = {(2,2)}
> >> > >>>> push(3) stack = {(3,2),(2,2)}
> >> > >>>> push(1) stack = {(1,1),(3,2),(2,2)}
>
> >> > >>>> where b in tuple (a,b) represents the min value upto current depth
> >> in
> >> > >>>> stack.
> >> > >>>> pop() and min() are straight forward.
>
> >> > >>>> On Mon, Sep 5, 2011 at 12:48 AM, Don <dondod...@gmail.com> wrote:
>
> >> > >>>>> Each element in the stack will contain not only its own value, but
> >> the
> >> > >>>>> min value at that depth of the stack:
>
> >> > >>>>> struct stackItemStruct
> >> > >>>>> {
> >> > >>>>> int value;
> >> > >>>>> int min;
> >> > >>>>> struct stackItemStruct *next;
> >> > >>>>> };
>
> >> > >>>>> typedef struct stackItemStruct stackItem;
>
> >> > >>>>> class stack
> >> > >>>>> {
> >> > >>>>> public:
> >> > >>>>> stack();
> >> > >>>>> void push(int v);
> >> > >>>>> int pop();
> >> > >>>>> int min();
> >> > >>>>> private:
> >> > >>>>> stackItem *_stack;
> >> > >>>>> };
>
> >> > >>>>> stack::stack()
> >> > >>>>> {
> >> > >>>>> _stack = 0;
> >> > >>>>> }
>
> >> > >>>>> void stack::push(int v)
> >> > >>>>> {
> >> > >>>>> stackItem newItem = new stackItem;
> >> > >>>>> newItem->value = newItem->min = v;
> >> > >>>>> if (_stack && (_stack->min < v) )
> >> > >>>>> newItem->min = _stack->min;
> >> > >>>>> newItem->next = _stack;
> >> > >>>>> _stack = newItem;
> >> > >>>>> }
>
> >> > >>>>> int stack::pop()
> >> > >>>>> {
> >> > >>>>> int result = 0;
> >> > >>>>> if (_stack)
> >> > >>>>> {
> >> > >>>>> result = _stack->val;
> >> > >>>>> stackItem *tmp = _stack;
> >> > >>>>> _stack = tmp->next;
> >> > >>>>> delete tmp;
> >> > >>>>> }
> >> > >>>>> return result;
> >> > >>>>> }
>
> >> > >>>>> int stack::min()
> >> > >>>>> {
> >> > >>>>> return _stack ? _stack->min : 0;
> >> > >>>>> }
>
> >> > >>>>> On Sep 4, 12:08 pm, Sangeeta <sangeeta15...@gmail.com> wrote:
> >> > >>>>> > How would you design a stack which,in addition to push and
> >> pop,also
> >> > >>>>> > has a function min which returns the minimum element?push,pop
> >> and min
> >> > >>>>> > should all operate in O(1) time
>
> >> > >>>>> --
> >> > >>>>> You received this message because you are subscribed to the Google
> >> > >>>>> Groups "Algorithm Geeks" group.
> >> > >>>>> To post to this group, send email to algogeeks@googlegroups.com.
> >> > >>>>> To unsubscribe from this group, send email to
> >> > >>>>> algogeeks+unsubscr...@googlegroups.com.
> >> > >>>>> For more options, visit this group at
> >> > >>>>>http://groups.google.com/group/algogeeks?hl=en.
>
> >> > >>>> --
> >> > >>>> Nitin Garg
>
> >> > >>>> "Personality can open doors... but only Character can keep them
> >> open"
>
> >> > >>>> --
> >> > >>>> You received this message because you are subscribed to the Google
> >> > >>>> Groups "Algorithm Geeks" group.
> >> > >>>> To post to this group, send email to algogeeks@googlegroups.com.
> >> > >>>> To unsubscribe from this group, send email to
> >> > >>>> algogeeks+unsubscr...@googlegroups.com.
> >> > >>>> For more options, visit this group at
> >> > >>>>http://groups.google.com/group/algogeeks?hl=en.
>
> >> > >>> --
>
> >> > >>> **Please do not print this e-mail until urgent requirement. Go
> >> Green!!
> >> > >>> Save Papers <=> Save Trees
> >> > >>> *BharatKumar Bagana*
> >> > >>> **http://www.google.com/profiles/bagana.bharatkumar<
> >>http://www.google.com/profiles/bagana.bharatkumar>
> >> > >>> *
> >> > >>> Mobile +91 8056127652*
> >> > >>> <bagana.bharatku...@gmail.com>
>
> >> > >>> --
> >> > >>> You received this message because you are subscribed to the Google
> >> Groups
> >> > >>> "Algorithm Geeks" group.
> >> > >>> To post to this group, send email to algogeeks@googlegroups.com.
> >> > >>> To unsubscribe from this group, send email to
> >> > >>> algogeeks+unsubscr...@googlegroups.com.
> >> > >>> 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 algogeeks@googlegroups.com.
> >> > >> To unsubscribe from this group, send email to
> >> > >> algogeeks+unsubscr...@googlegroups.com.
> >> > >> 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 algogeeks@googlegroups.com.
> >> > > To unsubscribe from this group, send email to
> >> > > algogeeks+unsubscr...@googlegroups.com.
> >> > > For more options, visit this group at
> >> > >http://groups.google.com/group/algogeeks?hl=en.-Hide quoted text -
>
> >> > - Show quoted text -
>
> >> --
> >> You received this message because you are subscribed to the Google Groups
> >> "Algorithm Geeks" group.
> >> To post to this group, send email to algogeeks@googlegroups.com.
> >> To unsubscribe from this group, send email to
> >> algogeeks+unsubscr...@googlegroups.com.
> >> 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 algogeeks@googlegroups.com.
> > To unsubscribe from this group, send email to
> > algogeeks+unsubscr...@googlegroups.com.
> > For more options, visit
>
> ...
>
> read more »- Hide quoted text -
>
> - Show quoted text -
--
You received this message because you are subscribed to the Google Groups
"Algorithm Geeks" group.
To post to this group, send email to algogeeks@googlegroups.com.
To unsubscribe from this group, send email to
algogeeks+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/algogeeks?hl=en.
