Language: C++

#include <bits/stdc++.h>
using namespace std;
#define FOR(i, begin, end) for (ll i = (begin); i < (end); i++)
#define REP(i, n) FOR(i, 0, n)
#define IFOR(i, begin, end) for (ll i = (begin)-1; i >= (end); i--)
#define IREP(i, n) IFOR(i, n, 0)
#define SORT(a) sort(a.begin(), a.end())
#define ISORT(a) sort(a.begin(), a.end(), greater<ll>())
#define REVERSE(a) reverse(a.begin(), a.end())
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v)                                                              \
  cout << #v << "=(" << v[0];                                                  \
  FOR(i_debug, 1, v.size()) { cout << "," << v[i_debug]; }                     \
  cout << ")" << endl;
#define mdebug(m)                                                              \
  cout << #m << "=" << endl;                                                   \
  REP(i_debug, m.size()) {                                                     \
    REP(j_debug, m[i_debug].size()) { cout << m[i_debug][j_debug] << ","; }    \
    cout << endl;                                                              \
  }
#define Lower_bound(v, x)                                                      \
  distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x)                                                      \
  distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)

#define ll long long
// #define f first
// #define s second
#define mp make_pair
#define pb push_back
#define INF 1000000000000000000

using vec = vector<ll>;
using mat = vector<vec>;
using Pii = pair<ll, ll>;
using PiP = pair<ll, Pii>;
using PPi = pair<Pii, ll>;
using bvec = vector<bool>;
using Pvec = vector<Pii>;

template <typename T> void readv(vector<T> &a) { REP(i, a.size()) cin >> a[i]; }
void readv_m1(vector<int> &a) {
  REP(i, a.size()) {
    cin >> a[i];
    a[i]--;
  }
}

ll mod = 1000000007;

// https://qiita.com/drken/items/3b4fdf0a78e7a138cd9a#4-%E7%B4%AF%E4%B9%97-an
ll modpow(ll a, ll n, ll mod) {
  ll res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}

ll ctoi(const char c) {
  switch (c) {
  case '0':
    return 0;
  case '1':
    return 1;
  case '2':
    return 2;
  case '3':
    return 3;
  case '4':
    return 4;
  case '5':
    return 5;
  case '6':
    return 6;
  case '7':
    return 7;
  case '8':
    return 8;
  case '9':
    return 9;
  default:
    return -1;
  }
}

int main() {
  vector<vector<int>> dp(200005, vec(2019, 0));

  string S;
  cin >> S;
  REP(i, S.size()) {
    dp[i + 1][ctoi(S[i])] += 1;
    REP(j, 2019) {
      ll nextj = (j * 10 + ctoi(S[i])) % 2019;
      // if (nextj == 0) {
      //   // cout << j << endl;
      //   // cout << dp[i][j] << endl;
      // }
      dp[i + 1][nextj] += dp[i][j];
      // dp[i + 1][j] += dp[i][j];
    }
    // cout << dp[i + 1][0] << endl;
  }

  // cout << dp[8][0] << endl;
  ll ans = 0;
  REP(i, S.size() + 1) { ans += dp[i][0]; }
  cout << ans << endl;

  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:93:46: error: no matching function for call to 'std::vector<std::vector<int> >::vector(int, vec)'
   93 |   vector<vector<int>> dp(200005, vec(2019, 0));
      |                                              ^
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_vector.h:707:9: note: candidate: 'template<class _InputIterator, class> std::vector<_Tp, _Alloc>::vector(_InputIterator, _InputIterator, const allocator_type&) [with <template-parameter-2-2> = _InputIterator; _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  707 |         vector(_InputIterator __first, _InputIterator __last,
      |         ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:707:9: note:   template argument deduction/substitution failed:
a.cc:93:46: note:   deduced conflicting types for parameter '_InputIterator' ('int' and 'std::vector<long long int>')
   93 |   vector<vector<int>> dp(200005, vec(2019, 0));
      |                                              ^
/usr/include/c++/14/bits/stl_vector.h:678:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >]'
  678 |       vector(initializer_list<value_type> __l,
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:678:43: note:   no known conversion for argument 1 from 'int' to 'std::initializer_list<std::vector<int> >'
  678 |       vector(initializer_list<value_type> __l,
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:659:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, std::__type_identity_t<_Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; std::__type_identity_t<_Alloc> = std::allocator<std::vector<int> >]'
  659 |       vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:659:23: note:   no known conversion for argument 1 from 'int' to 'std::vector<std::vector<int> >&&'
  659 |       vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
      |              ~~~~~~~~~^~~~
/usr/include/c++/14/bits/stl_vector.h:640:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, const allocator_type&, std::false_type) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >; std::false_type = std::false_type]'
  640 |       vector(vector&& __rv, const allocator_type& __m, false_type)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:640:7: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_vector.h:635:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, const allocator_type&, std::true_type) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >; std::true_type = std::true_type]'
  635 |       vector(vector&& __rv, const allocator_type& __m, true_type) noexcept
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:635:7: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_vector.h:624:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&, std::__type_identity_t<_Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; std::__type_identity_t<_Alloc> = std::allocator<std::vector<int> >]'
  624 |       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:624:28: note:   no known conversion for argument 1 from 'int' to 'const std::vector<std::vector<int> >&'
  624 |       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
      |              ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:620:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  620 |       vector(vector&&) noexcept = default;
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:620:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:601:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  601 |       vector(const vector& __x)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:601:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:569:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(size_type, const value_type&, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; size_type = long unsigned int; value_type = std::vector<int>; allocator_type = std::allocator<std::vector<int> >]'
  569 |       vector(size_type __n, const value_type& __value,
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:569:47: note:   no known conversion for argument 2 from 'vec' {aka 'std::vector<long long int>'} to 'const std::vector<std::vector<int> >::value_type&' {aka 'const std::vector<int>&'}
  569 |       vector(size_type __n, const value_type& __value,
      |                             ~~~~~~~~~~~~~~~~~~^~~~~~~
/usr/include/c++/14/bits/stl_vector.h:556:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(size_type, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; size_type = long unsigned int; allocator_type = std::allocator<std::vector<int> >]'
  556 |       vector(size_type __n, const allocator_type& __a = allocator_type())
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:556:51: note:   no known conversion for argument 2 from 'vec' {aka 'std::vector<long long int>'} to 'const std::vector<std::vector<int> >::allocator_type&' {aka 'const std::allocator<std::vector<int> >&'}
  556 |       vector(size_type __n, const allocator_type& __a = allocator_type())
      |                             ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:542:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >]'
  542 |       vector(const allocator_type& __a) _GLIBCXX_NOEXCEPT
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:542:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:531:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector() [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  531 |       vector() = default;
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:531:7: note:   candidate expects 0 arguments, 2 provided