ReverseBits(leetcode190)

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?

public static int reverseBits(int n) {

    int result = 0;
    for (int i = 0; i < 32; i++) {
        result += n & 1;
        n >>>= 1;
        if (i < 31){
            result <<= 1;
        }
    }
    return result;

}

public  static int reverseBits2(int n) {
    return Integer.reverse(n);
}