chill21's blog

Distinct digits in a range using BIT
By chill21, history, 7 years ago, In English

You are given an array of size n find number of distinct digits in the numbers in a given range ? I know how to do it with segment tree , please help me to do it with Binary indexed tree .

thanks in advance :)

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7 years ago, # |
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You can use one BIT per digit so you can easily found the frequency of any given digit in a range. You can solve every query in O(D * log(N)) where D = 10.

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7 years ago, # |
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You know how to do it with segment tree then you must be familiar with the logic. Then I guess problem is in the implementation part.
Here is my solution.

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7 years ago, # |
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By the way if you have multiple queries which can be processed offline, this can also be done using square root decomposition (also referred to as Mo's algorithm).

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