Preparing this workspace.
Number of 1 Bits
Difficulty: Easy
Category: DSA
Topics: Divide and Conquer, Bit Manipulation
Asked at: Box, Cisco, Microsoft, Qualcomm
Given a positive integer `n`, write a function that returns the number of set bits in its binary representation (also known as the Hamming weight).
**Example 1:**
**Input:** n = 11
**Output:** 3
**Explanation:**
The input binary string **1011** has a total of three set bits.
**Example 2:**
**Input:** n = 128
**Output:** 1
**Explanation:**
The input binary string **10000000** has a total of one set bit.
**Example 3:**
**Input:** n = 2147483645
**Output:** 30
**Explanation:**
The input binary string **1111111111111111111111111111101** has a total of thirty set bits.
**Constraints:**
- `1 <= n <= 231 - 1`
**Follow up:** If this function is called many times, how would you optimize it?
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