DSA · Bit Manipulation · #129
Number of 1 Bits
Module 50 · difficulty 2/5·⏱ 30:00starts on first keystroke
Write a function `hammingWeight(n)` that takes a non-negative integer `n` and returns the number of set bits (`1` bits) in its binary representation — also known as the Hamming weight. The input is given as the integer's value (treat it as a 32-bit unsigned number). Return the count of `1` bits.
Examples
n = 11→3— 11 in binary is 1011, which has three 1 bits.n = 128→1— 128 in binary is 10000000, which has a single 1 bit.n = 2147483645→30— 2147483645 in binary is 1111111111111111111111111111101, which has thirty 1 bits.
Constraints
- · 0 <= n <= 2^31 - 1
- · n is a non-negative integer fitting in 32 bits.
Session phases
A · Clarify
B · Approach
C · Complexity
D · Edges
E · Code
F · Tradeoff
G · Score
Phase A — Clarify
Ask questions about input bounds, types, and edge constraints.
Ask the coach clarifying questions about the problem.
When you've covered this phase, advance to the next.