338. Counting Bits

Given an integer n, return an array ans of length n + 1 such that for each i (0 <= i <= n), ans[i] is the number of 1's in the binary representation of i.

Example 1:

Input: n = 2
Output: [0,1,1]
Explanation:
0 --> 0
1 --> 1
2 --> 10

Example 2:

Input: n = 5
Output: [0,1,1,2,1,2]
Explanation:
0 --> 0
1 --> 1
2 --> 10
3 --> 11
4 --> 100
5 --> 101

def countBits(self, n: int) -> List[int]:
	dp = [0] * (n+1)
	sub = 1
	for i in range(1, n+1):
		if 2 * sub == i:
			sub = i
		dp[i] = dp[i - sub] + 1
	return dp