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.

 1 class Solution { 2 public: 3     int hammingWeight(uint32_t n) { 4          5         int count = 0; 6          7         while(n) 8         { 9             n = (n & (n-1));10             count++;11         }12         return count;13     }14 };

191. Number of 1 Bits