Java 用Lambda來寫費氏數列

以前寫這個要透過遞迴
現在可以輕鬆寫了XD

import java.util.stream.Stream;

public class Test {
    public static void main(String []args){
        System.out.println(Fibonacci(10));
        System.out.println(Old_Fibonacci(10));
    }



    private static long Fibonacci(int n) {
        return Stream.iterate(new long[]{1, 1}, f -> new long[]{f[1], f[0] + f[1]})
                .limit(n)
                .reduce((in, out) -> out)
                .get()[0];
    }

    private static long Old_Fibonacci(int n) {
        if (n < 2)
            return n;
        else
            return Old_Fibonacci(n - 2) + Old_Fibonacci(n - 1);
    }
}