2017-06-15 18:06:07 +0000   |     algorithm leetcode bit manipulation   |   Viewed times   |    

题目

Write a function that takes an unsigned integer and returns the number of 1 bits it has (also known as the Hamming weight).

For example, the 32-bit integer 11 has binary representation 00000000000000000000000000001011, so the function should return 3.

1掩码切割最低位

时间复杂度 n is the length of int.

代码

public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int count = 0;
        for (int i = 0; i < 32; i++) {
            count += (n & 1);
            n >>= 1;
        }
        return count;
    }
}

结果

number-of-one-bits-1