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 int[] hai;
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int i;
   Scanner sca=new Scanner(System.in);
      hai=new int[sca.nextInt()+1];
      for(i=0;i<hai.length;i++)hai[i]=-1;
      System.out.println(fib(hai.length-1));
	}
	public static int fib(int n){
		if(n==0||n==1)return 1;
		if(hai[n]!=-1)return hai[n];
		hai[n]=fib(n-1)+fib(n-2);
		return hai[n];
	}

}