LeetCode 509: Fibonacci Number Solution

Problem Explanation

Explanation:

We can solve this problem using a simple iterative approach or a more optimized recursive approach with memoization.
The recursive approach involves calculating Fibonacci numbers recursively, and we can use memoization to store the already computed values to avoid redundant calculations.
We can create an array to store Fibonacci numbers up to n and then calculate the Fibonacci number for n using the previously computed values.
Time Complexity: O(n) as we calculate each Fibonacci number only once.
Space Complexity: O(n) for storing the Fibonacci numbers.

Solution Code

class Solution {
    public int fib(int n) {
        if (n <= 1) {
            return n;
        }
        int[] fibNums = new int[n + 1];
        fibNums[0] = 0;
        fibNums[1] = 1;
        for (int i = 2; i <= n; i++) {
            fibNums[i] = fibNums[i - 1] + fibNums[i - 2];
        }
        return fibNums[n];
    }
}

Frequently Asked Questions

How to solve LeetCode 509 (Fibonacci Number)?

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What is the time complexity of LeetCode 509 (Fibonacci Number)?

The time complexity for LeetCode 509 (Fibonacci Number) varies by solution. Check the detailed explanation section for specific complexities in Java, C++, and Python implementations.

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509. Fibonacci Number