Number of Even and Odd Bits — LeetCode 2595 Python Solution

The problem

You are given a positive integer n. Let even denote the number of even indices in the binary representation of n with value 1.

Python solution

class Solution:
    def evenOddBit(self, n: int) -> List[int]:
        ans = [0, 0]
        i = 0
        while n:
            ans[i] += n & 1
            i ^= 1
            n >>= 1
        return ans

Complexity

Pattern: Bit Manipulation

Use XOR, masks and the low-bit trick to replace whole data structures with an integer. LeetCode 2595. Number of Even and Odd Bits is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Bit Manipulation.

The bit manipulation guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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