Java解决青蛙跳台阶问题流程

public class TestDemo {
    public static int frogJump(int n){
        if(n == 1 || n == 2){   //当n为前2阶台阶的时候，n是几就是几
            return n;
        }else{
            return frogJump(n-2)+frogJump(n-1);//求n阶台阶的几种跳法
        }
    }
 
 
    public static void main(String[] args) {
        System.out.println(frogJump(1));
        System.out.println(frogJump(2));
        System.out.println(frogJump(3));
        System.out.println(frogJump(4));
 
    }
}

第二种写法：循环(迭代）实现 
public class TestDemo {
    public static int frogJump2(int n){
        if(n == 1 || n==2){
            return n;
        }
        int f1 = 1;
        int f2 = 2;
        int f3 = 0;
        for (int i = 3; i <= n; i++) {
            f3 = f1+f2;
            f1 = f2;
            f2 = f3;
        }
        return f3;
 
    }
    public static void main(String[] args) {
        System.out.println(frogJump2(1));
        System.out.println(frogJump2(2));
        System.out.println(frogJump2(3));
        System.out.println(frogJump2(4));
        System.out.println(frogJump2(5));
        System.out.println(frogJump2(45));
 
    }
}