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

#include <bits/stdc++.h>
#ifdef HIRO
#define d(f_, ...) printf((f_), ##__VA_ARGS__)
#else
#define d(f_, ...)
#endif

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pllll;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vllll;
typedef map<int, int> mii;
typedef map<long long, long long> mllll;
typedef queue<int> qi;
typedef queue<pair<int, int>> qp;
#define mp make_pair
#define pi 3.14159265358979323846
#define MAX max_element
#define MIN min_element
#define all(v) v.begin(), v.end()
#define gt(T) greater<T>()
#define sum(v) accumulate(v.begin(), v.end(), 0ll)
#define uni(v)                                                                 \\
  do {                                                                         \\
    sort(v.begin(), v.end());                                                  \\
    decltype(v)::iterator result = unique(v.begin(), v.end());                 \\
    v.erase(result, v.end());                                                  \\
  } while (0)
#define fi(init, n) for (int i = init; i < n; ++i)
#define fj(init, n) for (int j = init; j < n; ++j)
#define fk(init, n) for (int k = init; k < n; ++k)
#define zero(x) memset(x, 0, sizeof(x))
#define negative(x) memset(x, ~0, sizeof(x))
#define bitsum(x) __builtin_popcount(x)
const ll MOD = 1e9 + 7;
const int INF = 1e9;
const int di[] = {0, 1, 0, -1};
const int dj[] = {1, 0, -1, 0};

template <typename T> T gcd(T a, T b) { return b ? gcd(b, a % b) : a; }
template <typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
template <typename T> int finder(vector<T> vec, T number) {
  auto itr = find(vec.begin(), vec.end(), number);
  size_t index = distance(vec.begin(), itr);
  if (index != vec.size())
    return 1;
  else
    return 0;
}
ll frac(ll n) {
  if (n == 0)
    return 1;
  return (n * frac(n - 1)) % MOD;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

int main(int argc, char **argv) {
#ifdef HIRO
  string quiz(argv[1]);
  string id(argv[2]);
  string filename("input/" + quiz + "/" + id + ".txt");
  ifstream fin(filename);
  if (fin.peek() == ifstream::traits_type::eof()) {
    cout << "No input.";
    return 0;
  }
  ifstream cin(filename);
  std::cin.rdbuf(cin.rdbuf());
#endif
  // ll res = 0;
  // ll n;
  // cin >> n;
  // ll n, m;
  // cin >> n >> m;
  // ll n, m, k;
  // cin >> n >> m >> k;
  string S;
  cin >> S;
  int N = S.size();
  int P = 2019;
  //   if(P==2||P==5){
  //     long long res=0;
  //     for(int i=0;i<N;i++) if((S[N-i-1]-'0')%P==0) res+=N-i;
  //     return res;
  // }
  vector<long long> val(P, 0);
  long long tenfactor = 1;
  long long cur = 0;
  val[cur]++;

  for (int i = 0; i < N; i++) {
    cur = (cur + (S[N - i - 1] - '0') * tenfactor) % P;
    tenfactor = (tenfactor * 10) % P;
    val[cur]++;
  }
  long long res = 0;
  for (int p = 0; p < P; p++)
    res += val[p] * (val[p] - 1) / 2;
  cout << res << endl;
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#ifdef HIRO
#define d(f_, ...) printf((f_), ##__VA_ARGS__)
#else
#define d(f_, ...)
#endif

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pllll;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vllll;
typedef map<int, int> mii;
typedef map<long long, long long> mllll;
typedef queue<int> qi;
typedef queue<pair<int, int>> qp;
#define mp make_pair
#define pi 3.14159265358979323846
#define MAX max_element
#define MIN min_element
#define all(v) v.begin(), v.end()
#define gt(T) greater<T>()
#define sum(v) accumulate(v.begin(), v.end(), 0ll)
#define uni(v)                                                                 \\
  do {                                                                         \\
    sort(v.begin(), v.end());                                                  \\
    decltype(v)::iterator result = unique(v.begin(), v.end());                 \\
    v.erase(result, v.end());                                                  \\
  } while (0)
#define fi(init, n) for (int i = init; i < n; ++i)
#define fj(init, n) for (int j = init; j < n; ++j)
#define fk(init, n) for (int k = init; k < n; ++k)
#define zero(x) memset(x, 0, sizeof(x))
#define negative(x) memset(x, ~0, sizeof(x))
#define bitsum(x) __builtin_popcount(x)
const ll MOD = 1e9 + 7;
const int INF = 1e9;
const int di[] = {0, 1, 0, -1};
const int dj[] = {1, 0, -1, 0};

template <typename T> T gcd(T a, T b) { return b ? gcd(b, a % b) : a; }
template <typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
template <typename T> int finder(vector<T> vec, T number) {
  auto itr = find(vec.begin(), vec.end(), number);
  size_t index = distance(vec.begin(), itr);
  if (index != vec.size())
    return 1;
  else
    return 0;
}
ll frac(ll n) {
  if (n == 0)
    return 1;
  return (n * frac(n - 1)) % MOD;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

int main(int argc, char **argv) {
#ifdef HIRO
  string quiz(argv[1]);
  string id(argv[2]);
  string filename("input/" + quiz + "/" + id + ".txt");
  ifstream fin(filename);
  if (fin.peek() == ifstream::traits_type::eof()) {
    cout << "No input.";
    return 0;
  }
  ifstream cin(filename);
  std::cin.rdbuf(cin.rdbuf());
#endif
  ll ans = 0;
  // ll n;
  // cin >> n;
  // ll n, m;
  // cin >> n >> m;
  // ll n, m, k;
  // cin >> n >> m >> k;
  string s;
  cin >> s;
  ll num_mul = 0;
  int n = s.size();
  set<int> st[n];
  int k = 2019;
  fi(0, n) {
    ll remainder = 0;
    ll prefix_found = 0;
    fj(i, n) {
      remainder = (10 * remainder + (s[j] - '0')) % k;
      if (st[j].count(remainder)) {
        break;
      }
      st[j].insert(remainder);
      // printf("remainder: %lld\\n", remainder);
      if (remainder == 0)
        prefix_found++;
    }
    // printf("prefix_found: %lld\\n", prefix_found);
    num_mul += prefix_found * (prefix_found + 1) / 2;
  }
  cout << num_mul << endl;
  return 0;
}