leecode 解题总结：191. Number of 1 Bits

#include <iostream>
#include <stdio.h>
#include <vector>
#include <string>
using namespace std;
/*
问题:
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.

输入:此题主要是计算二进制中1的个数。一个简单的方法是
n&(n-1)，比如7=111,6=110,每一次相与都会把最低位的1给删除掉

输入:
7
11
0
1
-1
输出:
3
3
0
1
32
*/

typedef unsigned uint32_t ;

class Solution {
public:
    int hammingWeight(uint32_t n) {
		int count = 0;
        while(n)
		{
			n = n & (n-1);
			count++;
		}
		return count;
    }
};

void process()
{
	 vector<int> nums;
	 int value;
	 unsigned num;
	 Solution solution;
	 vector<int> result;
	 while(cin >> num )
	 {
		 int answer = solution.hammingWeight(num);
		 cout << answer << endl;
	 }
}

int main(int argc , char* argv[])
{
	process();
	getchar();
	return 0;
}