[leetcode]-190. Reverse Bits

Reverse bits of a given 32 bits unsigned integer.

Example:

Input: 43261596
Output: 964176192
Explanation: 43261596 represented in binary as 00000010100101000001111010011100, 
             return 964176192 represented in binary as 00111001011110000010100101000000.

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

代码如下：

uint32_t reverseBits(uint32_t n) {
    uint32_t r=0;
    int i;
    for(i=0;i<32;i++)
    {
        r=(r<<1)+(n&1);
        n=n>>1;
    }
    return r;
}