[Leetcode 190, Easy] Reverse Bits

Problem:

Reverse bits of a given 32 bits unsigned integer.

For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as00111001011110000010100101000000).

Follow up:

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

Related problem: Reverse Integer
Analysis:

Solutions:

C++:

uint32_t reverseBits(uint32_t n) {
        uint32_t ri = 0;
        for(int i = 0; i < 32; ++i) {
            ri = ri << 1;
            ri += n % 2;
            n = n >> 1;
        }
        return ri;
    }

Java:

Python: