位 1 的个数

/*
 * This solution uses Java Streams to count the number of '1' bits in a 32-bit integer.
 * First, the integer is converted to a binary string. Then, we filter the characters to count only '1's.
 * The result is the number of '1' bits.
 */
import java.util.stream.Collectors;

public class Solution {
    public long hammingWeight(int n) {
        // Convert to binary string and count '1's
        return Integer.toBinaryString(n).chars()
                .filter(ch -> ch == '1')
                .count();
    }
}