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

/*~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=
    WRITER:kakitamasziru/OxOmisosiru
~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=*/
#ifdef LOCAL_JUDGE
#define _GLIBCXX_DEBUG // FOR THE DEBUG! COMMENT OUT THIS WHEN SUBMITTING!
#endif
#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <cstdint>   // int64_t, int*_t
#include <iomanip>
#include <iostream> // cout, endl, cin
#include <limits>   //setprecision
#include <string>   // string, to_string, stoi
#include <tuple>    // tuple, make_tuple
#include <utility>  // pair, make_pair
#include <vector>   // vector
// #include <cstdio> // printf
#include <cmath>  //abs,,,
#include <deque>  // deque
#include <map>    // map
#include <math.h> //pow,,,
#include <queue>  // queue, priority_queue
#include <set>    // set
#include <stack>  // stack
// #include <unordered_map> // unordered_map
// #include <unordered_set> // unordered_set
#include <bitset> // bitset
// #include <cctype> // isupper, islower, isdigit, toupper, tolower
// It is so troublesome that I include bits/stdc++.h !
using namespace std;

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;
}
const long long INF = 100100100100;
const int MOD = 2019;
typedef pair<int, int> P;
// NのM乗を求める(繰り返し二乗法)
long long mod_pow(long long N, long long M) {
  if (M == 0)
    return 1;
  long long res = mod_pow((N * N) % MOD, M / 2);
  // 最下位ビット(*N)が1の時は単独でNをかける
  if (M & 1)
    res = (res * N) % MOD;

  return res %= MOD;
}
long long nCr(long long n, long long r) {
  long long A = 1, B = 1;
  // Aが分子Bが1/r!
  for (long long i = n - r + 1; i <= n; i++) {
    A = A * i % MOD;
  }
  for (long long i = 1; i <= r; i++) {
    B = B * i % MOD;
  }
  B = mod_pow(B, MOD - 2);
  B %= MOD;
  // Bは割るのではなく掛ける
  return (A * B) % MOD;
}

long long gcd(long long a, long long b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}

long long lcm(long long a, long long b) { return a * b / gcd(a, b); }

long long A, B;

bool ok(long long key, long long index) {
  string S = to_string(index);
  long long nagasa = S.size();
  if (index * A + nagasa * B > key)
    return true;
  else if (index * A + nagasa * B <= key)
    return false;
}

long long binary_search(long long key, long long size) {
  // left,right,midはいずれもindex
  long long left = -1, right = size;
  while (right - left > 1) {
    long long mid = left + (right - left) / 2;
    long long hantei = ok(key, mid);
    if (hantei)
      right = mid;
    else
      left = mid;
  }
  if (left == -1)
    return 0;
  return left;
}

// dp[i][j]:i桁目の余りがj
string S;
long long kind[2019];
long long num[200001];

int main() {
  cin >> S;
  int N = S.size();
  for (int i = 0; i < 2019; i++) {
    kind[i] = 0;
  }
  num[N - 1] = S.at(N - 1) - '0';
  kind[num[N - 1]] = 1;
  kind[0] = 1;
  for (int i = N - 2; i >= 0; i--) {
    long long A = S.at(i) - '0';
    num[i] = (A * mod_pow(10, N - i - 1) + num[i + 1]) % MOD;
    kind[num[i]]++;
  }
  long long ans = 0;
  for (int i = 0; i < 2019; i++) {
    ans += (kind[i] * (kind[i] - 1)) / 2;
  }

  cout << ans << endl;

  // PLEASE GIVE ME THE "ACCEPTED" !
}


Error: TLE

Fixed submission:

/*~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=
    WRITER:kakitamasziru/OxOmisosiru
~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=*/
#ifdef LOCAL_JUDGE
#define _GLIBCXX_DEBUG // FOR THE DEBUG! COMMENT OUT THIS WHEN SUBMITTING!
#endif
#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <cstdint>   // int64_t, int*_t
#include <iomanip>
#include <iostream> // cout, endl, cin
#include <limits>   //setprecision
#include <string>   // string, to_string, stoi
#include <tuple>    // tuple, make_tuple
#include <utility>  // pair, make_pair
#include <vector>   // vector
// #include <cstdio> // printf
#include <cmath>  //abs,,,
#include <deque>  // deque
#include <map>    // map
#include <math.h> //pow,,,
#include <queue>  // queue, priority_queue
#include <set>    // set
#include <stack>  // stack
// #include <unordered_map> // unordered_map
// #include <unordered_set> // unordered_set
#include <bitset> // bitset
// #include <cctype> // isupper, islower, isdigit, toupper, tolower
// It is so troublesome that I include bits/stdc++.h !
using namespace std;

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;
}
const long long INF = 100100100100;
const int MOD = 2019;
typedef pair<int, int> P;
// NのM乗を求める(繰り返し二乗法)
long long mod_pow(long long N, long long M) {
  if (M == 0)
    return 1;
  long long res = mod_pow((N * N) % MOD, M / 2);
  // 最下位ビット(*N)が1の時は単独でNをかける
  if (M & 1)
    res = (res * N) % MOD;

  return res %= MOD;
}
long long nCr(long long n, long long r) {
  long long A = 1, B = 1;
  // Aが分子Bが1/r!
  for (long long i = n - r + 1; i <= n; i++) {
    A = A * i % MOD;
  }
  for (long long i = 1; i <= r; i++) {
    B = B * i % MOD;
  }
  B = mod_pow(B, MOD - 2);
  B %= MOD;
  // Bは割るのではなく掛ける
  return (A * B) % MOD;
}

long long gcd(long long a, long long b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}

long long lcm(long long a, long long b) { return a * b / gcd(a, b); }

long long A, B;

bool ok(long long key, long long index) {
  string S = to_string(index);
  long long nagasa = S.size();
  if (index * A + nagasa * B > key)
    return true;
  else if (index * A + nagasa * B <= key)
    return false;
}

long long binary_search(long long key, long long size) {
  // left,right,midはいずれもindex
  long long left = -1, right = size;
  while (right - left > 1) {
    long long mid = left + (right - left) / 2;
    long long hantei = ok(key, mid);
    if (hantei)
      right = mid;
    else
      left = mid;
  }
  if (left == -1)
    return 0;
  return left;
}

// dp[i][j]:i桁目の余りがj
string S;
priority_queue<int, vector<int>, greater<int>> Q;

int main() {
  cin >> S;
  int N = S.size();
  long long now = 0;
  long long ans = 0;
  int next = -1;
  while (Q.empty()) {
    next++;
    if (next == N)
      break;
    for (int i = next; i < N; i++) {
      int A = S.at(i) - '0';
      now = now * 10 + A;
      now %= MOD;
      if (now == 0) {
        Q.push(i);
        ans++;
        break;
      }
      // cout << now << endl;
    }
    now = 0;
  }
  now = 0;
  int place = 0;
  while (!Q.empty()) {
    place = Q.top();
    // cout << place << endl;
    Q.pop();
    for (int i = place; i < N; i++) {
      int B = S.at(i) - '0';
      now = now * 10 + B;
      now %= MOD;
      if (now == 0) {
        Q.push(i);
        ans++;
      }
    }
    now = 0;
  }

  cout << ans << endl;

  // PLEASE GIVE ME THE "ACCEPTED" !
}