# Number of 1 Bits – Leetcode Solution

In this post, we are going to solve the 191. Number of 1 Bits problem of Leetcode. This problem 191. Number of 1 Bits is a Leetcode easy level problem. Let’s see the code, 191. Number of 1 Bits – Leetcode Solution.

Contents

## Problem

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

Note:

• Note that in some languages, such as Java, there is no unsigned integer type. In this case, the input will be given as a signed integer type. It should not affect your implementation, as the integer’s internal binary representation is the same, whether it is signed or unsigned.
• In Java, the compiler represents the signed integers using 2’s complement notation. Therefore, in Example 3, the input represents the signed integer. -3.

### Example 1 :

``````Input: n = 00000000000000000000000000001011
Output: 3
Explanation: The input binary string 00000000000000000000000000001011 has a total of three '1' bits.``````

### Example 2 :

``````Input: n = 00000000000000000000000010000000
Output: 1
Explanation: The input binary string 00000000000000000000000010000000 has a total of one '1' bit.``````

### Example 3 :

``````Input: n = 11111111111111111111111111111101
Output: 31
Explanation: The input binary string 11111111111111111111111111111101 has a total of thirty one '1' bits.``````

### Constraints

• The input must be a binary string of length `32`.

Now, let’s see the code of 191. Number of 1 Bits – Leetcode Solution.

# Diameter of Binary Tree – Leetcode Solution

### 191. Number of 1 Bits – Solution in Java

```public class Solution {
// you need to treat n as an unsigned value
public int hammingWeight(int n) {
int count =0 ;
while(n != 0){
count++;
n = (n & (n-1));

}
return count;
}
}```

### 191. Number of 1 Bits – Solution in C++

```class Solution {
public:
int hammingWeight(uint32_t n) {
int count =0 ;
while(n != 0){
count++;
n = (n & (n-1));

}
return count;
}
};```

### 191. Number of 1 Bits – Solution in Python

```def hammingWeight(self, n):
"""
:type n: int
:rtype: int
"""
c = 0
while n:
n &= n - 1
c += 1
return c```

Note: This problem 191. Number of 1 Bits is generated by Leetcode but the solution is provided by CodingBroz. This tutorial is only for Educational and Learning purpose.