斐波那契数列 · 通项公式

通项公式：

import java.util.*;
public class Main {
    public static void main(String[] args) throws Exception{
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double a = Math.sqrt(5.0);
        double temp1 = (1.0 + a)/2.0;
        double temp2 = (1.0 - a)/2.0;
        int r = (int)(1.0/a*(Math.pow(temp1, n) - Math.pow(temp2, n)));
        System.out.println(r);
    }
}