problem338

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338. Counting Bits (Medium)

Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1's in their binary representation and return them as an array.

Example 1:

Input: 2
Output: [0,1,1]

Example 2:

Input: 5
Output: [0,1,1,2,1,2]

Follow up:

• It is very easy to come up with a solution with run time O(n*sizeof(integer)). But can you do it in linear time O(n) /possibly in a single pass?
• Space complexity should be O(n).
• Can you do it like a boss? Do it without using any builtin function like __builtin_popcount in c++ or in any other language.

Related Topics

[Bit Manipulation] [Dynamic Programming]

Similar Questions

1. Number of 1 Bits (Easy)

Hints

Hint 1

You should make use of what you have produced already.

Hint 2

Divide the numbers in ranges like [2-3], [4-7], [8-15] and so on. And try to generate new range from previous.

Hint 3

Or does the odd/even status of the number help you in calculating the number of 1s?