# Leetcode191: Number of 1 Bits solution

Here, we will help to understand about how to find out Number of 1 Bits solution of leet code 191 with code and algorithm.

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

Example:

```Input: n = 00000000000000000000000000011011
Output: 4
Explanation: The input binary string 00000000000000000000000000011011 has a total of four '1' bits.

Input: n = 00000000000000000000000010000010
Output: 2
Explanation: The input binary string 00000000000000000000000010000010 has a total of two '1' bit.

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

Note: The input must be aÂ binary stringÂ of lengthÂ `32`.

### Explanation:

This problem belongs to bits category where by using bitwise operator, you have to find out number of set bits in a given number.

### Algorithm 1:

• Iterate over bits of number
• If bit is 1 then increment the count variable.
• If bit is 0 then skip the increment the count.
• return count

## Number of 1 Bits code in C++

Code 1:

```#include <iostream>

using namespace std;

int hammingWeight(uint32_t n) {
int count = 0;

while(n) {
if(n & 1) {
count++;
}
n >>= 1;
}
return count;
}

int main()
{
cout<<hammingWeight(10);

return 0;
}```

Code 2:

```#include <iostream>
#include <algorithm>

using namespace std;

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

int main()
{
cout<<hammingWeight(10);

return 0;
}```

Output:

```Input: 10 in bit's: 1010
Output: 2```

Output:

`abc`

To check more leetcode problem’s solution. Pls click given below link:

https://www.techieindoor.com/category/leetcode/

Posted in C++, Easy, Leetcode