1332. Number of 1 Bits

描述

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

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样例

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

又是一道可以用逻辑运算的投机取巧的题目，二进制里有多少个1；

class Solution {
public:
    /**
     * @param n: an unsigned integer
     * @return: the number of ’1' bits
     */
    int hammingWeight(unsigned int n) {
        // write your code here
        int sum=0;
        while(n>0){
            n=n&(n-1);
            sum++;
        }
        return sum;
    }
};