【剑指Offer 15】二进制中1的个数

位移

/**
 * 剑指 Offer 15. 二进制中1的个数
 * https://leetcode.cn/problems/er-jin-zhi-zhong-1de-ge-shu-lcof/
 *
 * 思路：位移
 * */
public class Solution1 {
    public int hammingWeight(int n) {
        int count = 0;
        while (n != 0) {
            count += n & 1; // 判断最低位是否是 1
            n = n >>> 1; // 无符号右移
        }
        return count;
    }
}

位运算

/**
 * 剑指 Offer 15. 二进制中1的个数
 * https://leetcode.cn/problems/er-jin-zhi-zhong-1de-ge-shu-lcof/
 *
 * 思路：位运算
 * 110100
 * 110011 &
 * */
public class Solution2 {
    public int hammingWeight(int n) {
        int count = 0;
        while (n != 0) {
            n &= n - 1; // 消掉最低位的 1
            count++;
        }
        return count;
    }
}