玲珑杯 ACM热身赛 #2.5 A 记忆化搜索+瞎搞

#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <list>
#include <queue>
#include <stack>
#include <cmath>
#include <cstring>
#define N 998244353
#define LL long long int
int n,m;
using namespace std;
LL dp[505][505];
LL dfs(int he,int qiu,int lim)
{
//    if(n%m!=0&&lim==n/m+1)
//        return 0;
    if(he==0)
    {
        if(qiu!=0)
            return 0;
        else
            return 1;
    }
    if(dp[he][qiu]) return dp[he][qiu];
    LL rec=0;
    for(int i=0;i<=qiu&&i<lim;i++)
        rec+=dfs(he-1,qiu-i,lim),rec%=N;
    dp[he][qiu]=rec;
    return rec;
}
int main()
{
    cin.sync_with_stdio(false);
    cin>>n>>m;
    LL ans=0;
    for(int i=n;i>=0;i--)
    {
        memset(dp,0,sizeof(dp));
        ans+=dfs(m-1,n-i,i),ans%=N;
    }
    cout<<ans*m%N<<endl;
    return 0;
}