0190: Reverse Bits

Problem Statement

Reverse bits of a given 32 bits signed integer.

Example 1:

Input: n = 43261596

Output: 964176192

Explanation:

Integer Binary
43261596 00000010100101000001111010011100
964176192 00111001011110000010100101000000

Example 2:

Input: n = 2147483644

Output: 1073741822

Explanation:

Integer Binary
2147483644 01111111111111111111111111111100
1073741822 00111111111111111111111111111110

Constraints:

  • 0 <= n <= 231 - 2
  • n is even.

Follow up: If this function is called many times, how would you optimize it?

Code Solution

class Solution:
    def reverseBits(self, n: int) -> int:
        out = 0
        for ix in range(31, -1, -1):
            out = (out << 1) | (n & 1)
            n = n >> 1
        return out