Number of 1 Bits

Desicription

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

Example 1:

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

Example 2:

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

Solution

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