递推算法-斐波那契数列（兔子繁殖）

1、

 int a = 1, b = 1, c = 0;        System.out.println("斐波那契数列前20项为：");        System.out.print(a + "\t" + b + "\t");        //因为前面还有两个1、1 所以i<=18        for (int i = 1; i <= 18; i++) {            c = a + b;            a = b;            b = c;            System.out.print(c + "\t");        }

2、

  int arr[] = new int[20];        arr[0] = arr[1] = 1;        for (int i = 2; i < arr.length; i++) {            arr[i] = arr[i - 1] + arr[i - 2];        }        System.out.println("斐波那契数列的前20项如下所示：");        for (int i = 0; i < arr.length; i++) {            System.out.print(arr[i] + "\t");        }

3、此处已经用到递归

   System.out.println("斐波那契数列的前20项为：");        for (int j = 1; j <= 20; j++) {            System.out.print(getFibo(j) + "\t");        }    }    private static int getFibo(int i) {        if (i == 1 || i == 2)            return 1;        else            return getFibo(i - 1) + getFibo(i - 2);    }