#include <bits/stdc++.h>   using namespace std;   const int SZ = 8e6 + 10;   const int INF = 1e9 + 10;   const int mod = 998244353;   const long double eps = 1e-8;   long long read() {     long long n = 0;     char a = getchar();     bool flag = 0;     while (a >  9  || a <  0 ) {       if (a ==  - ) flag = 1;       a = getchar();     }     while (a <=  9  && a >=  0 ) {       n = n * 10 + a -  0 , a = getchar();     }     if (flag) n = -n;     return n;   }   int a[SZ], f[1010][1010], b[SZ], c[SZ];   int main() {     int n = read(), k = read();     for (int i = 1; i <= n; i++) a[i] = read();     sort(a + 1, a + 1 + n);     for (int i = 1; i <= n; i++) {       for (int j = i + 1; j <= n; j++) {         b[++b[0]] = a[j] - a[i];       }     }     sort(b + 1, b + 1 + b[0]);     b[0] = unique(b + 1, b + 1 + b[0]) - b - 1;     int ans = 0;     for (int j = 1; j <= b[0]; j++) {       int minx = b[j];       if (minx > 1e5 / (k - 1)) break;       for (int i = 1; i <= n; i++) f[i][1] = f[i - 1][1] + 1;       for (int l = 2; l <= k; l++) {         for (int i = 2, lst = 0; i <= n; i++) {           while (lst < i && a[lst + 1] <= a[i] - minx) lst++;           f[i][l] = f[lst][l - 1];         }         for (int i = 1; i <= n; i++) (f[i][l] += f[i - 1][l]) %= mod;       }       c[j] = f[n][k];     }     for (int j = 1; j <= b[0]; j++)       (ans += 1ll * b[j] * (c[j] - c[j + 1] + mod) % mod) %= mod;     printf( %d n , ans);   }   