Yes, navin thats a good solution...

... we dont need to work on the whole array but of  size k x k (k rows and
k columsn only). Rest of the array we can simply ignore..

complexity of youngify is O(k) for every removing every element.
we have to remove k-1 elements so complexity of whole operation is
o(k*k).

Refer this pdf:
http://lyle.smu.edu/~saad/courses/cse3358/ps5/problemset5sol.pdf

Regards
Saurabh


On Mon, May 21, 2012 at 10:00 AM, Navin.nitjsr <[email protected]>wrote:

> We can consider the 2-d matrix as a heap(also called Young Tableau).
> We just need to heapify(Youngify) it   k-1    times,then the element at
> 0,0 will be kth smallest element.
> This means we need to remove the  k-1 smallest elements from matrix and
> still maintaining its Row-Col sorted property.
> Youngify algo:-
> 1:- put a sentinel value (i,e, INF) 0,0
> 2:- Now push it leftwards/downwards to maintain the initial property of
> matrix
> 3:- If at any point the current element is smaller than both its left and
> down element, then STOP.
>
> This is an in-place operation.
> We need to consider the sentinel value as highest value,not present in the
> matrix.
> It works.Although the matrix  is being modified.
>
>
>
> On Monday, 10 October 2011 04:45:52 UTC+5:30, Ankur Garg wrote:
>>
>> Given a 2D matrix which is both row wise and column wise sorted. Propose
>> an algorithm for finding the kth smallest element in it in least time
>> complexity
>>
>> A General Max Heap can be used with k space and n+klogk complexity
>>
>> Any other solution  or even a way by which we dont scan the whole matrix
>> to find the solution ?
>>
>> I
>>
>
> On Monday, 10 October 2011 04:45:52 UTC+5:30, Ankur Garg wrote:
>>
>> Given a 2D matrix which is both row wise and column wise sorted. Propose
>> an algorithm for finding the kth smallest element in it in least time
>> complexity
>>
>> A General Max Heap can be used with k space and n+klogk complexity
>>
>> Any other solution  or even a way by which we dont scan the whole matrix
>> to find the solution ?
>>
>> I
>>
>
> On Monday, 10 October 2011 04:45:52 UTC+5:30, Ankur Garg wrote:
>>
>> Given a 2D matrix which is both row wise and column wise sorted. Propose
>> an algorithm for finding the kth smallest element in it in least time
>> complexity
>>
>> A General Max Heap can be used with k space and n+klogk complexity
>>
>> Any other solution  or even a way by which we dont scan the whole matrix
>> to find the solution ?
>>
>> I
>>
>
> On Monday, 10 October 2011 04:45:52 UTC+5:30, Ankur Garg wrote:
>>
>> Given a 2D matrix which is both row wise and column wise sorted. Propose
>> an algorithm for finding the kth smallest element in it in least time
>> complexity
>>
>> A General Max Heap can be used with k space and n+klogk complexity
>>
>> Any other solution  or even a way by which we dont scan the whole matrix
>> to find the solution ?
>>
>> I
>>
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