Description

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.

Solution

我們把要翻轉的數n從低位到高位依次放入res中，放入的方式就是判斷此時n的最低位是0還是1，如果是1就將res++

public class Solution {
    public int reverseBits(int n) {
        if (n == 0) return 0;
        
        int res = 0;
        for (int i = 0; i < 32; i++) {
        	res = res << 1;
            if
 
 ((n & 1) == 1) res++;
            n = n >> 1;
        }
        return res;
    }
}