变态跳台阶

Posted 2022-08-11 wuyi_all_in

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。

---

class Solution 
public:
    int jumpFloorII(int number) 
        if(number==0)return 0;
        //record[i]需要第i级台阶有多少种跳法
        vector<int>record(number+1,0);
        //record_1[i-1]需要第i级台阶有多少种跳法
        vector<int>record_1(number+1,0);
        record[0]=1;
        record[1]=1;
        record[2]=2;
        record_1[0]=1;
        record_1[1]=2;
        record_1[2]=4;
        for(int i=3;i<=number;i++)
        
            record[i]=record_1[i-1];
            record_1[i]=record_1[i-1]+record[i];
        
        return record_1[number-1];
    
;

---

class Solution 
public:
    int jumpFloorII(int number) 
        if(number==0)return 0;
        //record_1[i-1]需要第i级台阶有多少种跳法
        vector<int>record_1(number+1,0);
        
        record_1[0]=1;
        record_1[1]=2;
        record_1[2]=4;
        for(int i=3;i<=number;i++)
        
            record_1[i]=record_1[i-1]*2;
        
        return record_1[number-1];
    
;