LeetCode - Reverse Bits

Reverse Bits

2015.4.17 05:42

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

Solution:

　　Is this problem worthy enough to appear in an interview?

Accepted code:

// 1AC, I'm beginning to doubt the quality of leetcode problem set...
class Solution {
public:
    uint32_t reverseBits(uint32_t n) {
        int i;
        uint32_t ans = 0;
        for (i = 0; i < sizeof(uint32_t) * 8; ++i) {
            ans = (ans << 1) | (n & 1);
            n >>= 1;
        }
        
        return ans;
    }
};