1188C Array Beauty && 1189F Array Beauty

#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn=1e3+2;
const int mod=998244353;
int n,k,ans;
int a[maxn];
int dp[maxn][maxn];
void DP(){
    for (int i=1;i<=a[n]/(k-1)+1;i++){
        dp[0][0]=1;
        for (int l=1,r=0;l<=n;l++){
            while (a[r+1]+i<=a[l]) r++;
            dp[l][0]=dp[l-1][0];
            for (int pos=1;pos<=l&&pos<=k;pos++) dp[l][pos]=(dp[l-1][pos]+dp[r][pos-1])%mod;
        }
        ans=(ans+dp[n][k])%mod;
    }
}
int main(){
    scanf("%d%d",&n,&k);
    for (int i=1;i<=n;i++) scanf("%d",&a[i]);
    sort(a+1,a+n+1);
    DP();
    printf("%d",ans);
    return 0;
}