[algogeeks] Re: Cliched 'k' largest elements in billion numbers: Heaps or median-of-medians?

2011-12-12 Thread Gene
If N is big enough so that all data will not fit in main memory and k is small enough so that the k top elements fit in memory, then the heap is likely to be the best.This is because disk access is so incredibly slow compared to memory access: A few milliseconds (10^-3) vs. a few nanoseconds

Re: [algogeeks] A binary tree question

2011-12-12 Thread atul anand
there was error in else part and one more while loop was missing :- here is the correct algo:- while(!isEmpty(s1) || !isEmpty(s2)) { while(!isEmpty(s1)) { val=pop(s1); print : val-data;

[algogeeks] Re: Backtracking algorithm for binpacking-like problem

2011-12-12 Thread Lucifer
@ania My idea is based on the post that i had replied in http://groups.google.com/group/algogeeks/browse_thread/thread/8a58ea05c96f811b?hl=en# A simple tweak to the above algo can be used to solve bin-packing problem in a (probably) faster time. First, please go through the above post. The

[algogeeks] Re: Backtracking algorithm for binpacking-like problem

2011-12-12 Thread Lucifer
A slightly different approach on the lines of data access and ease of understanding: 1) Sort the input array i.e the weights array W[N] . 2) Identify the no. of unique elements in it and create the following: a) Count[R] - count of each unique element based on its sorted order.

[algogeeks] Re: Sub-array problem

2011-12-12 Thread Lucifer
@ Gaurav I don't think the above nlogn approach will work. If i m not wrong, the above nlogn approach is a modification of the nlogn algo for maximum continuous subset problem. I have a doubt with the crossing subarray solution. I see that your if and while loop breaks out if totalsum =K is not

[algogeeks] Best algorithm possible

2011-12-12 Thread KAY
Given an array of elements find the largest possible number that can be formed by using the elements of the array eg: 10 9 ans: 910 eg: 2 3 5 78 ans: 78532 -- You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this group, send email to

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread sravanreddy001
Sort the numbers based on the 'index_position' (starting at most significat digit) -- a modified version of MSD radix to be used. or sort the numbers as sorting the strings, (print all in desc order). -- You received this message because you are subscribed to the Google Groups Algorithm

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread Lucifer
+1 @sravan On Dec 12, 8:55 pm, sravanreddy001 sravanreddy...@gmail.com wrote: Sort the numbers based on the 'index_position' (starting at most significat digit) -- a modified version of MSD radix to be used. or sort the numbers as sorting the strings,  (print all in desc order). -- You

[algogeeks] Find Largest number in log(n)

2011-12-12 Thread sagar pareek
Hi every one. Can we find largest number from an unsorted array in log(n) ? -- **Regards SAGAR PAREEK COMPUTER SCIENCE AND ENGINEERING NIT ALLAHABAD -- You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this group, send email to

[algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread sagar pareek
I think... First round of tournament sort. :D On Mon, Dec 12, 2011 at 8:02 AM, sagar pareek sagarpar...@gmail.com wrote: Hi every one. Can we find largest number from an unsorted array in log(n) ? -- **Regards SAGAR PAREEK COMPUTER SCIENCE AND ENGINEERING NIT ALLAHABAD --

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread Dave
@Sravanreddy: There is more to it, as the cases {865, 86, 7} and {865, 86, 2} show. Dave On Dec 12, 9:55 am, sravanreddy001 sravanreddy...@gmail.com wrote: Sort the numbers based on the 'index_position' (starting at most significat digit) -- a modified version of MSD radix to be used. or

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread KAY
@sravan- Sorting would fail in this case: consider 8,91, 9 sorting in desc order is going to give us 91, 9, 8. printing this is going to give us 9198. However, a bigger number can be formed 9891. After sorting lexicographically, we have to consider whether tied elements in list can be combined

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread sagar pareek
Yes Mr. DoN First round of Tournament sort results in log(n) time for finding largest no. n/2+n/4+n/8 results n/(2^i) where ^ = power On Mon, Dec 12, 2011 at 8:16 AM, Don dondod...@gmail.com wrote: No. To find the largest number in an unsorted array requires looking at

[algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread Dave
@Sagar: Don is correct. n/2+n/4+n/8+... ~= n. But even the first round, involving n/2 comparisons, is O(n). Dave On Dec 12, 11:23 am, sagar pareek sagarpar...@gmail.com wrote: Yes Mr. DoN First round of Tournament sort results in log(n) time for finding largest no. n/2+n/4+n/8      

[algogeeks] Nice question

2011-12-12 Thread KAY
If for a number n digits long, the absolute difference between adjacent digits is given, how to find out the number of different numbers with these absolute differences ? for eg, if n=5 and the absolute differences are 3 2 5 1 then 1 possible number is 6 3 5 0 1(because |6-3|=3,|3-5|=2 and so

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread Ankur Garg
Agree with dave..Its still O(n) On Mon, Dec 12, 2011 at 10:57 PM, Dave dave_and_da...@juno.com wrote: @Sagar: Don is correct. n/2+n/4+n/8+... ~= n. But even the first round, involving n/2 comparisons, is O(n). Dave On Dec 12, 11:23 am, sagar pareek sagarpar...@gmail.com wrote: Yes Mr.

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread Lucifer
Thinking on the same lines: 1) First sort the array in descending order.. A[n] 2) Use the following equation solve the prob: L(n) = the largest no. that can be formed by placing the A[n] in (n-2) possible positions of L(n-1)... Complexity : O(nlogn) + O(n^2) What do u guys think? On Dec

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread Lucifer
@above.. just to add to the above post... L(n) is basically reordering of the elements of A[n] which would produce the largest possible integer when read from L(0) to L(n). On Dec 12, 11:07 pm, Lucifer sourabhd2...@gmail.com wrote: Thinking on the same lines: 1) First sort the array in

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread ankit gupta
apply MAXHEAPIFY on root ode and extract the root node -- 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

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread Ankur Garg
Max Heapify is O(n). On Mon, Dec 12, 2011 at 11:43 PM, ankit gupta ankit.itc...@gmail.comwrote: apply MAXHEAPIFY on root ode and extract the root node -- You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this group, send email to

Re: [algogeeks] MYSIS AND DRISHTI-SOFT

2011-12-12 Thread aayush jain
thanx Anika.. -- 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,

Re: [algogeeks] MYSIS AND DRISHTI-SOFT

2011-12-12 Thread aayush jain
@rahul we post these qus bcos in this group lots of members r there. -- 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

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread ankit gupta
maxheapify is lg(n)..check coremen -- 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

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread ankit gupta
http://www.cse.iitk.ac.in/users/dsrkg/cs210/applets/sorting/heapSort/heapSort.html for reference -- 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,

[algogeeks] Re: Backtracking algorithm for binpacking-like problem

2011-12-12 Thread Gene
Guys, if you can find a solution that is not exponential time in the worst case you are going to be famous because this problem is NP-Hard in the strong sense. I.e. there is not even a pseudo-polynomial time algorithm. To get a perfect solution every time, you can't do better than heuristic

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread Dipit Grover
^it cant get better than O(n) apparently. Just applying max-heapify once would not yield the max element. You need to construct a heap for it, which is no less than O(n). -- You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this group,

[algogeeks] Re: Backtracking algorithm for binpacking-like problem

2011-12-12 Thread Lucifer
@Gene Great information.. Wasn't aware of the above cited finding... Thanks.. @ For all active followers of this post.. The problem posted by ania is a slight modification of the bin-packing problem as pointed out above because here the no. of bins to be filled is fixed and the capacity (of the

[algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread Gene
Exactly. Really you should see this with almost no thought. It's called an adversary argument and goes like this. Since you don't know the order of elements in A, envision them as being put in order by an adversary that always knows in advance what element you're going to examine next. Now no

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread Ankur Garg
By Max Heapify I thought u meant to say u are making a Max Heap .. In case you use Coreman Definition Of max Heapify it just heapifies assuming the heap has been formed, But u need to make a max Heap first dude :) P.S- Clarify your concepts before posting the link :( On Tue, Dec 13, 2011 at

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread Dave
@Kay: 9918 is bigger than 9891. :-) Dave On Dec 12, 11:23 am, KAY amulya.manches...@gmail.com wrote: @sravan- Sorting would fail in this case: consider   8,91, 9 sorting in desc order is going to give us 91, 9, 8. printing this is going to give us 9198. However, a bigger number can be

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread Lucifer
@Kay: In the algo given above i don't think sorting is required...Only the following is enough.. Use the following equation solve the prob: L(n) = the largest no. that can be formed by placing the A[n] in (n-2) possible positions of L(n-1)... Complexity : O(n^2) On Dec 13, 3:07 am, Dave

[algogeeks] Re: Best algorithm possible

2011-12-12 Thread Lucifer
An nlogn approach... would require validation from others.. Normal sorting in decreasing order shall solve this problem with one modification which is a special case and i.e. if 2 nos. to be sorted are in the following format: abc and abcX ... where X itself is a number of the form (def...)

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread saurabh singh
@all..Well I am no expert but my logic says its impossible to pick the best unless and untill you look at each and every individual.Isn't this logic enough? On Tue, Dec 13, 2011 at 12:32 AM, Ankur Garg ankurga...@gmail.com wrote: By Max Heapify I thought u meant to say u are making a Max Heap

Re: [algogeeks] Re: Find Largest number in log(n)

2011-12-12 Thread Prakash D
only the number of comparisons is log(n) On Mon, Dec 12, 2011 at 11:04 PM, Ankur Garg ankurga...@gmail.com wrote: Agree with dave..Its still O(n) On Mon, Dec 12, 2011 at 10:57 PM, Dave dave_and_da...@juno.com wrote: @Sagar: Don is correct. n/2+n/4+n/8+... ~= n. But even the first round,

Re: [algogeeks] Re: Best algorithm possible

2011-12-12 Thread amrit harry
@kay bigger number is 9918 not 9891... On Mon, Dec 12, 2011 at 11:39 PM, Lucifer sourabhd2...@gmail.com wrote: @above.. just to add to the above post... L(n) is basically reordering of the elements of A[n] which would produce the largest possible integer when read from L(0) to L(n). On Dec

Re: [algogeeks] Removing same character(s) in a group

2011-12-12 Thread atul anand
for ababc - ab is common..so removing ab we get abc. then in abcabc - abc is commonso removing abc we get abc ?? what is the difference in this case On Mon, Dec 12, 2011 at 7:52 PM, top coder topcode...@gmail.com wrote: For example if aabbabc is given as input after first iteration, it

Re: [algogeeks] Removing same character(s) in a group

2011-12-12 Thread Amol Sharma
question is not clear...plz specify clearly what's the objective.. -- Amol Sharma Third Year Student Computer Science and Engineering MNNIT Allahabad http://gplus.to/amolsharma99 http://twitter.com/amolsharma99http://in.linkedin.com/pub/amol-sharma/21/79b/507http://youtube.com/amolsharma99

Re: [algogeeks] Removing same character(s) in a group

2011-12-12 Thread kartik sachan
+1 amol sharma...what u want ??.output should be shown at every step or u want final ans?? -- 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

Re: [algogeeks] Re: Best algorithm possible

2011-12-12 Thread atul anand
@Lucifer : if i am not getting it wrong then are you trying to say find all permutation of the given number ?? On Mon, Dec 12, 2011 at 11:39 PM, Lucifer sourabhd2...@gmail.com wrote: @above.. just to add to the above post... L(n) is basically reordering of the elements of A[n] which would

Re: [algogeeks] Removing same character(s) in a group

2011-12-12 Thread atul anand
well 1st part can be done of removing similar character , for the 2nd iteration where you want to remove continuous duplicate sub string then i guess this can be done :- for example :- input : aabbabc 1st iteration : ababc for 2nd iteration consider queue 1) maintain front value inserted int

Re: [algogeeks] Re: Best algorithm possible

2011-12-12 Thread Dipit Grover
@Lucifer (Regarding your latest approach) - I guess you meant string based comparison sort in the first step, as in 9 would be greater than 10. The special case seems correct but I doubt the complexity being nlog n, considering the special case. -- You received this message because you are

Re: [algogeeks] Sub-array problem

2011-12-12 Thread Gaurav Kumar
You are right the algorithm is based on the max subarray problem. The difference is the logic to get the crossingSubArray() method. The way it works is like this: The outer while loop, makes sure that left position or right position at least one of this should be between lo and hi values