public:
    int jumpFloorII(int number) {
        //使用递归的暴力解法
        int shu[20]={0};
        shu[0]=1;
        shu[1]=1;
        shu[2]=2;
        int i,j,k;
        for(i=3;i<=20;i+=1){
            for(j=0;j<=i-1;j+=1){
                shu[i]+=shu[j];
            }
        }
        return shu[number];
    }
};