Fenwick Tree (BIT)

#1

Now we try to implement the 2nd additional operation of an order-statistic tree i.e. find the kth smallest element.

Algo :

kth smallest element lies in range [1,N].
if number of elements smaller than or equal to some x is >= k then kth smallest element lies in range [1,x]
else kth smallest element lies in range [x + 1, N].

Using these observations we apply binary search and to find number of elements less than some number x we use sum(1, x) operation of the BIT.

what is the time complexity?

#2

@shahpankti931,
O(log(n)*log(n))
Complexity of Binary Search = log(n),
Complexity of BIT query = log(n).

#3

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