func_code_string: #include <bits/stdc++.h>   const long long mod = 998244353;   using namespace std;   pair<long long, long long> dp[20][2][1 << 10];   int k;   int s[20];   long long pw[20];   pair<long long, long long> solve(int i, bool U, int mask) {     if (i < 0) return {0, 1};     pair<long long, long long> &ret = dp[i][U][mask];     if (ret.first + 1) return ret;     ret = {0, 0};     int L = U ? 9 : s[i];     for (int e = 0; e <= L; e++) {       int Mask = mask | (mask > 0 ? (1 << e) : ((e > 0) * (1 << e)));       if (__builtin_popcount(Mask) > k) continue;       pair<long long, long long> temp = solve(i - 1, U || e < s[i], Mask);       ret.first += temp.first + temp.second * e % mod * pw[i] % mod;       ret.first %= mod;       ret.second += temp.second;       ret.second %= mod;     }     return ret;   }   int main() {     ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);     pw[0] = 1;     for (int i = 1; i <= 18; i++) pw[i] = pw[i - 1] * 10LL % mod;     long long l, r;     cin >> l >> r >> k;     for (int i = 0; i < 18; i++) s[i] = r % 10, r /= 10;     memset(dp, -1, sizeof dp);     long long ans = solve(17, 0, 0).first;     l--;     for (int i = 0; i < 18; i++) s[i] = l % 10, l /= 10;     memset(dp, -1, sizeof dp);     cout << ((ans - solve(17, 0, 0).first) % mod + mod) % mod;     return 0;   }   