java算法之斐波那契数列

public class Fibonacci {
    public static void main(String[] args) {
        int fibonacci = Recursion(10);
        System.out.println(fibonacci);
        System.out.println(sum(3));
    }
    public static int Recursion(int n){

        if(n==1){
            return 0;
        }

        if(n==2){
            return 1;
        }
        return Recursion(n-1)+Recursion(n-2);
    }
    public static int sum(int n) {
        int a = 0;
        while(n>=1) {
            a = a+Recursion(n);
            n--;
        }
        return a;
        
    }
}