PU Number of 1 Bits

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.

C Solution:

int hammingWeight(uint32_t n) {
    int res = 0;
    while (n) {
        res++;
        n &= n - 1;
    }
    return res;
}

Summary:

• nothing to say, you know or you don't know.

LeetCode: 191. Number of 1 Bits