变态跳台阶

题目描述

一只青蛙一次可以跳上1级台阶，也可以跳上2级……它也可以跳上n级。求该青蛙跳上一个n级的台阶总共有多少种跳法。

 

思路

number = 1时，total_ways = 1;  f(1) = 1

number = 2时，total_ways = 2;  f(2) = f(1) + 1

number = 3时，total_ways = 4;  f(3) = 1 + f(1)  + f(2) 

class Solution {
public:
    int jumpFloorII(int number) {
        int one_floor = 1;
        int two_florr = 2;
        int total_ways = 0;
        if(number == 1) return 1;
        if(number == 2) return 2;       
        if(number > 2) total_ways = pow(2,number-1);
        return total_ways;
    }
};