Java用递归和遍历实现斐波那契数列

• 遍历

    public static void main(String[] args) {
        Fibonacci test = new Fibonacci();
        System.out.println(test.f(5));
    }

    public int f(int n) {
        if (n == 1 || n == 2) {
            return 1;
        }
        int first = 1;
        int second = 1;
        int num = 0;
        for (int i = 3; i <= n; i++) {
            num = first + second;
            first = second;
            second = num;
        }
        return num;
    }
}

• 递归

public class Fibonacci {
    public static void main(String[] args) {
        Fibonacci test = new Fibonacci();
        System.out.println(test.f(5));
    }

    public int f(int n) {
        if (n == 1 || n == 2) {return 1;}
        return f(n - 1) + f(n - 2);
    }
}