191. 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.

Solution:

Another question that is dealing with bitwise operation.

The idea is similar, get the rightmost digit by n & 1 and right shift n while counting the number of '1' bits until n equals 0.

 public int hammingWeight(int n) {  
     int count=0;  
     while(n!=0){  
       count+=(n&1);  
       n=n>>>1;  
     }  
     return count;  
   }