C++ 解法, 执行用时: 2ms, 内存消耗: 352KB, 提交时间: 2020-08-25

class Solution {
public:
    int jumpFloorII(int number) {
        if(number<=0)
            return 0;
        if(number==1)    return 1;
        if(number==2)    return 2;
        vector<int> memo (number+1);
        int sum=1;
        for(int i=2;i<=number;++i){
            memo[i]=sum+1;
            sum+=memo[i];
        }
        return memo[number];
    }
};

C++ 解法, 执行用时: 2ms, 内存消耗: 356KB, 提交时间: 2021-06-01

class Solution {
public:
    int jumpFloorII(int number) {
        int* arr = new int[number+1];
        arr[0] = 0;
        arr[1] = 1;
        for (int i = 2; i < number + 1;i++){
            int t = 0;
            for (int j = 1; j < i; j++)
                t += arr[j];
            arr[i]=t + 1;
        }
        int ret = arr[number];
        delete[] arr;
        return ret;
    }
};

C++ 解法, 执行用时: 2ms, 内存消耗: 356KB, 提交时间: 2021-05-29

class Solution {
public:
    int jumpFloorII(int number) {
        int *a = new int[number+1];
        a[0] = 1;
        a[1] = 1;
        for(int i = 2;i <= number;i++){
            a[i] = 0;
            for(int j = i-1;j >= 0; j--)
                a[i]+=a[j];
        }
        return a[number];
    }
};

C++ 解法, 执行用时: 2ms, 内存消耗: 356KB, 提交时间: 2021-05-26

class Solution {
public:
    int jumpFloorII(int number) {
        vector<int>dp(number+1,0);
        dp[1]=1;
        dp[2]=2;
        int sum=3;
        for(int i=3;i<=number;i++){
            dp[i]=sum+1;
            sum+=dp[i];
        }
        return dp[number];
    }
};

C++ 解法, 执行用时: 2ms, 内存消耗: 356KB, 提交时间: 2021-05-26

class Solution {
public:
    int jumpFloorII(int number) {
        if(number==0||number==1)
            return 1;
        if(number==2)
            return 2;
        int sum=2;

        for(int i=3;i<=number;++i)
        {
            sum=2*sum;
        }
        return sum;
    }
};