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{
    public static int fib(int n, int num[], boolean data[]){
        if(!(data[n])){
            data[n] = true;
            num[n] = fib(n-1,num,data) + fib(n-2,num,data);
            return num[n];
        }
        else
            return num[n];
    }
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int num[] = new int[n+1];
        boolean data[] = new boolean[n+1];
        num[0] = num[1] = 1;
        data[0] = data[1] = true;
        System.out.println(fib(n,num,data));
    }
}