338. Counting Bits
Bit Manipulation, DP, Review, AMateList ·Problem Statement
link: LeetCode.cn LeetCode
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:
Input: n = 2
Output: [0,1,1]
Input: n = 5
Output: [0,1,1,2,1,2]
Solution Approach
Algorithm
Implement
class Solution:
def countBits(self, n: int) -> List[int]:
res = [0] * (n + 1)
for i in range(n + 1):
res[i] = res[i >> 1] + (i & 1)
return res