Codeforces 1027E Inverse Coloring 【DP】

 

Codeforces 1027E Inverse Coloring

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题目链接

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#include<bits/stdc++.h>
using namespace std;
#define N 1010
#define LL long long
#define Mod 998244353
int n,k;
LL dp[N][N],ans=0;
LL sum[N][N];
int main(){
    cin>>n>>k;
    dp[0][0]=1;
    for(int i=1;i<=n;i++)
        for(int j=1;j<=i;j++)
            for(int p=1;p<=j;p++)
                dp[i][j]=(dp[i][j]+dp[i-p][min(j,i-p)])%Mod;
    for(int i=n;i>=1;i--)dp[n][i]=(dp[n][i]-dp[n][i-1]+Mod)%Mod;
    for(int i=1;i<=n;i++)
        for(int j=1;j*i<k;j++)
            ans=(ans+dp[n][i]*dp[n][j]%Mod)%Mod;
    ans=(ans*2)%Mod;
    printf("%lld",ans);
    return 0;
}