# LeetCode 191. Number of 1 Bits

## Intuition

- Check how many 1 bits are there in the binary representation of
`n`

. - Using the right shift operation, check whether the last bit of
`n`

is 1 (by checking whether`n`

is odd).

## Approach

- Initialise
`ans`

to 0. - While
`n`

is greater than 0 (i.e., the binary representation contains at least one 1 bit):- Increase
`ans`

if the last bit of`n`

is odd (i.e., the binary representation of n is 1).

- Increase

Pseudocode of `hammingWeight()`

:

1 | hammingWeight(n): |

## Complexity

Time complexity: $O(logn)$.

- $logn$ iterations to calculate how many 1 bits are in the binary representation.

Space complexity: $O(1)$.

## Code

1 | class Solution { |