(java)leetcode Number of 1 Bits

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

For example, the 32-bit integer ’11' has binary representation

00000000000000000000000000001011

,
so the function should return 3.

思路:把这个数转换成2进制数，然后统计1出现的次数就行了

代码如下(已通过leetcode)

public class Solution {

// you need to treat n as an unsigned value

public int hammingWeight(int n) {

String str=Integer.toBinaryString(n);

//System.out.println(str);

int count=0;

for(int i=0;i<str.length();i++) {

if(str.charAt(i)=='1') count++;

}

return count;

}

}