斐波那契數列的遞歸實現和非遞歸實現

package java_study.JianZhiOffer;

import org.junit.Test;

/**
 * Created by ethan on 2015/6/23.
 * No9 斐波那契數列的遞歸實現和非遞歸實現
 */
public class No9Fibonacci {
    // 斐波那契數列
    public int fibonacci(int x){
        if (x==0) return 1;
        if (x==1) return 1;
        return fibonacci(x-1)+fibonacci(x-2);
    }

    // 斐波那契數組實現
    public int fibonacci_arr(int x){
        int[] arr = new int[x+1];
        arr[0] = 1;
        arr[1] = 1;
        for (int i=2; i<x+1; i++){
            arr[i] = arr[i-1]+arr[i-2];
        }
        return arr[x];
    }

    @Test
    public void test(){
        System.out.println(fibonacci(9));
        System.out.println(fibonacci_arr(9));
    }
}