juniorFibonacci Series
Why is the naive recursive approach inefficient?
Updated Apr 28, 2026
Short answer
It recalculates the same subproblems multiple times.
Deep explanation
The Fibonacci sequence is defined by the recurrence relation $F_n = F_{n-1} + F_{n-2}$. It recalculates the same subproblems multiple times.
Real-world example
Modeling population growth in ideal conditions.
Common mistakes
- Using a 1-based index when the interviewer expects 0-based.
Follow-up questions
- What is the 5th Fibonacci number?