Calculate the area of a circle
Detailed guide and Python implementation for the 'Calculate the area of a circle' problem.
1. Concept Overview
The 'Calculate the area of a circle' problem is a key challenge in the Numbers section.
This implementation focuses on easy-level logic in Python.
We prioritize technical accuracy and code readability in our provided solutions.
2. Real-World Applications
3. Visual Intuition
Visualizing the logic flow for Calculate the area of a circle.
4. Prerequisites
5. Step-by-Step Thinking
1. Understand the problem
Read the problem statement for Calculate the area of a circle carefully.
2. Formulate brute force
Draft a simple iterative solution.
3. Identify inefficiency
Look for redundant calculations.
4. Optimize search path
Use hashing or sorting to speed up the process.
5. Final Implementation
Clean up the code for production standards.
Problem Statement
Write a function area_of_circle(radius) that takes a non-negative number radius and returns the area of a circle with that radius, rounded to 2 decimal places.
Use the formula: Area = π × radius². Use math.pi or 3.14159265358979 for π.
- •0 <= radius <= 10^4
Examples
area_of_circle(5)
78.54
Area = π × 5² = π × 25 = 78.5398... ≈ 78.54.
area_of_circle(1)
3.14
Area = π × 1² = π ≈ 3.14.
area_of_circle(7)
153.94
Area = π × 7² = π × 49 = 153.938... ≈ 153.94.
Need a Hint?
Edge Cases to Watch
- Empty input structures
- Single element inputs
- Large numerical bounds
Ready to Solve?
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Interview Insights & Variations
Complexity Analysis Breakdown
Why Time: Directly evaluates all possibilities.
Why Space: Uses standard local memory.
Why Time: Optimized paths reduce total operations.
Why Space: May trade memory for speed.
Optimized Solution Python Code
Optimized Solution Python Code
import math
def area_circle_opt(r):
return math.pi * r**2Brute Force Code (Spoiler Guarded)
Brute Force Code (Spoiler Guarded)
def area_circle_brute(r):
return 3.14159 * r * rAlgorithm Pattern Checklist
When dealing with Numbers data patterns.
Core Prerequisites
Revision Key Notes
Common Mistakes & Pitfalls
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