leetcode_191题——Number of 1 Bits（外运算）

Number of 1 Bits

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Question Solution

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.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

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Bit Manipulation

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这道题考虑按位与运算和位的左移右移就可以了

#include<iostream>
#include<bitset>
typedef unsigned int uint32_t;

using namespace std;

int hammingWeight(uint32_t n)
{
	unsigned int temp=1;
	int result=0;
	for(int i=0;i<32;i++)
	{
		int temp2=temp<<i;
		if((n&temp2)!=0)
			result+=1;
	}
	return result;
}

int main()
{
	cout<<hammingWeight(11)<<endl;

}