Java实现斐波那契数列（递归+遍历）

1、遍历

package com.company;

public class Fibonacci {
    public  static void main(String[] args){
        Fibonacci test = new Fibonacci();
        System.out.println(test.Fibonacci(2));
    }

    public int Fibonacci(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;
    }
}

2、递归

package com.company;

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


    public int Fibonacci(int n){

        if (n == 1 || n == 2){
            return 1;
        }
        return Fibonacci_2(n-1) + Fibonacci_2(n - 2);
    }
}

3、效率对比

701408733
程序运行时间： 1ms
701408733
程序运行时间： 1875ms