Problem p02702 (C++) — buggy submission, verdict: Time Limit Exceeded

/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author
 */

// doot diddly donger cuckerino Hahahahahah
// Created by White Knife on 15/04/20.
#pragma GCC optimize("O3")
#pragma GCC target("sse4")
#pragma GCC target("popcnt")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace __gnu_cxx;
using namespace std;

// @formatter:off
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
#define sz(x) (long long)(x).size()
#define sim template <typename T
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \\
  sim > typename enable_if<sizeof dud<T>(0) x 1, debug &>::type operator<<(T i)
sim > struct rge {
  T b, e;
};
sim > rge<T> range(T i, T j) { return rge<T>{i, j}; }
sim > auto dud(T *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) {
    cerr << boolalpha << i;
    ris;
  }
  eni(==) { ris << range(all(i)); }
  sim, typename U dor(pair<U, T> d) {
    ris << "(" << d.first << ", " << d.second << ")";
  }
  sim dor(rge<T> d) {
    *this << "[";
    for (auto it = d.b; it != d.e; ++it)
      *this << ", " + 2 * (it == d.b) << *it;
    ris << "]";
  }
#else
  sim dor(const T &) { ris; }
#endif
};
#define pr(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

struct IoSetup {
  IoSetup() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed << std::setprecision(12);
    std::cerr << std::fixed << std::setprecision(12);
  }
} iosetup;

template <typename T, typename U>
std::ostream &operator<<(std::ostream &os, const std::pair<T, U> &p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T, typename U>
std::istream &operator>>(std::istream &is, std::pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T>
std::ostream &operator<<(std::ostream &os, const std::vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

// @formatter:on

// @formatter:off
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vb = vector<bool>;

using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vpii = vector<pii>;
using vpll = vector<pll>;
template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ld PI = acos(-1);

template <typename T> T gcd(T x, T y) { return (y == 0) ? x : gcd(y, x % y); }
template <typename T, typename... Targs> T gcd(T x, Targs... y) {
  return gcd(x, gcd(y...));
}

template <typename T> inline T mini(T &x, T y) { return x = min(x, y); }
template <typename T> inline T maxi(T &x, T y) { return x = max(x, y); }
template <typename T> T rand(T x, T y) { return rand() % (y - x + 1) + x; }

mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
// @formatter:on

class DMultipleOf2019 {
public:
  void solveOne(istream &cin, ostream &cout) {}

  void solve(std::istream &cin, std::ostream &cout) {
    string s;
    cin >> s;
    int n = s.size();
    ll ans = 0;
    vector<ll> dp(2020, 0);
    //    dp[s[0] - '0']++;
    for (int i = 0; i < n; ++i) {
      int d = s[i] - '0';
      vector<ll> dp2(2020, 0);
      dp2[d] = 1;
      for (int j = 0; j < 2020; ++j) {
        if (dp[j]) {
          ll rem = (10 * j + d) % 2019;
          if (rem == 0) {
            ans += dp[j];
          }
          dp2[rem] += dp[j];
        }
      }

      dp = dp2;
    }
    cout << ans << '\\n';
  }
};

int main() {
  DMultipleOf2019 solver;
  std::istream &in(std::cin);
  std::ostream &out(std::cout);
  solver.solve(in, out);
  return 0;
}


Error: TLE

Fixed submission:

/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author
 */

// doot diddly donger cuckerino Hahahahahah
// Created by White Knife on 15/04/20.
#pragma GCC optimize("O3")
#pragma GCC target("sse4")
#pragma GCC target("popcnt")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace __gnu_cxx;
using namespace std;

// @formatter:off
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
#define sz(x) (long long)(x).size()
#define sim template <typename T
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \\
  sim > typename enable_if<sizeof dud<T>(0) x 1, debug &>::type operator<<(T i)
sim > struct rge {
  T b, e;
};
sim > rge<T> range(T i, T j) { return rge<T>{i, j}; }
sim > auto dud(T *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) {
    cerr << boolalpha << i;
    ris;
  }
  eni(==) { ris << range(all(i)); }
  sim, typename U dor(pair<U, T> d) {
    ris << "(" << d.first << ", " << d.second << ")";
  }
  sim dor(rge<T> d) {
    *this << "[";
    for (auto it = d.b; it != d.e; ++it)
      *this << ", " + 2 * (it == d.b) << *it;
    ris << "]";
  }
#else
  sim dor(const T &) { ris; }
#endif
};
#define pr(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

struct IoSetup {
  IoSetup() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed << std::setprecision(12);
    std::cerr << std::fixed << std::setprecision(12);
  }
} iosetup;

template <typename T, typename U>
std::ostream &operator<<(std::ostream &os, const std::pair<T, U> &p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T, typename U>
std::istream &operator>>(std::istream &is, std::pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T>
std::ostream &operator<<(std::ostream &os, const std::vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

// @formatter:on

// @formatter:off
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vb = vector<bool>;

using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vpii = vector<pii>;
using vpll = vector<pll>;
template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ld PI = acos(-1);

template <typename T> T gcd(T x, T y) { return (y == 0) ? x : gcd(y, x % y); }
template <typename T, typename... Targs> T gcd(T x, Targs... y) {
  return gcd(x, gcd(y...));
}

template <typename T> inline T mini(T &x, T y) { return x = min(x, y); }
template <typename T> inline T maxi(T &x, T y) { return x = max(x, y); }
template <typename T> T rand(T x, T y) { return rand() % (y - x + 1) + x; }

mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
// @formatter:on

class DMultipleOf2019 {
public:
  void solveOne(istream &cin, ostream &cout) {}

  void solve(std::istream &cin, std::ostream &cout) {
    string s;
    cin >> s;
    int n = s.size();
    vector<int> a(n);
    vector<ll> three(n + 1);
    for (int i = 0; i < n; ++i) {
      a[i] = (int(s[i]) - '0');
      three[i + 1] = three[i] + a[i];
    }
    auto divisbleby3 = [&](int l, int r) {
      return (three[r + 1] - three[l]) % 3 == 0;
    };

    set<ll> seen[n + 5];
    int res = 0;
    for (int i = 0; i < n; ++i) {
      int rem = 0;
      ll pref = 0;
      for (int j = i; j < n; ++j) {
        rem = (10 * rem + a[j]) % 673;
        if (seen[j].count(rem)) {
          break;
        }
        seen[j].insert(rem);
        if (rem == 0 and divisbleby3(i, j)) {
          pref++;
        }
      }
      res += pref * (pref + 1) / 2;
    }
    cout << res << '\\n';
  }
};

int main() {
  DMultipleOf2019 solver;
  std::istream &in(std::cin);
  std::ostream &out(std::cout);
  solver.solve(in, out);
  return 0;
}