Problem

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

Example

Input: 11
Output: 3
Explanation: Integer 11 has binary representation 00000000000000000000000000001011 

Input: 128
Output: 1
Explanation: Integer 128 has binary representation 00000000000000000000000010000000

Code

static int var = [](){
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();
class Solution {
public:
    int hammingWeight(uint32_t n) {
        int count = 0;
        while(n!=0){
            count += n % 2;
            n = n/2;
        }
        return count;
    }
};

Result

191. Number of 1 Bits.png