Problem:
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Fibonacci Number

Write a program which prints $n$-th fibonacci number for a given integer $n$. The $n$-th fibonacci number is defined by the following recursive formula:

\begin{equation*}
fib(n)= \left \{
\begin{array}{ll}
1　 & (n = 0) \\
1　 & (n = 1) \\
fib(n - 1) + fib(n - 2) & \\
\end{array}
\right.
\end{equation*}

Input

An integer $n$ is given.

output

Print the $n$-th fibonacci number in a line.

Constraints

$0 \leq n \leq 44$

Sample Input 1

3

Sample Output 1

3

Solution in JAVA (judge verdict: Accepted)



import java.util.Scanner;

public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int n = sc.nextInt();
        int ans = getFibonach(n);
        System.out.println(ans);
    }

    private static int getFibonach(int idx) {
        int[] arr = new int[idx + 1];
        arr[0] = 1;
        arr[1] = 1;
        for (int i = 2; i <= idx; i++) {
            arr[i] = arr[i - 1] + arr[i - 2];
        }
        return arr[idx];
    }
}