[Bit Manipulation] Number of 1 Bits (Hamming Weight)

[sudosf]

Problem

Write a function that takes a positive integer and returns the number of set bits (1s) in its binary representation.

References

• LeetCode: https://leetcode.com/problems/number-of-1-bits/description/
• GFG: https://www.geeksforgeeks.org/problems/count-total-set-bits-1587115620/1
• Sheet: https://www.risingbrain.org/sheet#bit-manipulation (Basic Bit Operations DSA Patterns course - AlgoMonster / freeCodeCamp #2)
• Parent: Pattern: Bit Manipulation #150

Difficulty

🟢 Easy

Companies

Amazon, Sumo Logic, Paytm

Notes

Language: Java
Trick: n & (n-1) clears the lowest set bit. Count how many times you can do this before n becomes 0.