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

#include <algorithm>
#include <bitset>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;

// conversion
//------------------------------------------
inline int toInt(string s) {
  int v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T> inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}

// math
//-------------------------------------------
template <class T> inline T sqr(T x) { return x * x; }

// typedef
//------------------------------------------
typedef long long LL;

typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;

// container util
//------------------------------------------
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())

// repetition
//------------------------------------------
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) FOR(i, 0, n)

// constant
//--------------------------------------------
const double PI = acos(-1.0);

// clear memory
#define CLR(a) memset((a), 0, sizeof(a))

// debug
#define dump(x) cerr << #x << " = " << (x) << endl;
#define debug(x)                                                               \\
  cerr << #x << " = " << (x) << " (L" << __LINE__ << ")"                       \\
       << " " << __FILE__ << endl;
const LL MOD = 1e9 + 7;
// vector <vector<int>> x(20, vector<int> (20)), y(20,vector<int> (20));
/*int counter_1 (int x) {
    if(x == 0) return 0;
    return counter_1(x >> 1) + (x & 1);
}*/

int main() {
  string s;
  cin >> s;
  int n = s.size();
  vector<LL> T(n + 1, 0);
  map<int, LL> cnt;
  LL k = 1;
  cnt[0]++;
  for (int i = n - 1; i >= 0; i--) {
    LL tmp = s[i] - '0';
    T[i] = (T[i + 1] + (tmp * k)) % 2019;
    // cout << tmp << ' ' << T[i+1] << endl;
    cnt[T[i]]++;
    k = (k * 10) % 2019;
  }
  LL ans = 0;
  for (auto &x : cnt) {
    int m = x.second;
    ans += (m * (m - 1)) / 2;
    // cout << x.first << ' ' << x.second << endl;
  }
  cout << ans << endl;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string>
#include <utility>
#include <vector>

using namespace std;

// conversion
//------------------------------------------
inline int toInt(string s) {
  int v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T> inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}

// math
//-------------------------------------------
template <class T> inline T sqr(T x) { return x * x; }

// typedef
//------------------------------------------
typedef long long LL;

typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<string, int> PSI;

// container util
//------------------------------------------
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())

// repetition
//------------------------------------------
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) for (int i = 0; i < (n); i++)

// constant
//--------------------------------------------
const double PI = acos(-1.0);

// clear memory
#define CLR(a) memset((a), 0, sizeof(a))

// debug
#define dump(x) cerr << #x << " = " << (x) << endl;
#define debug(x)                                                               \\
  cerr << #x << " = " << (x) << " (L" << __LINE__ << ")"                       \\
       << " " << __FILE__ << endl;
const LL MOD = 1e9 + 7;
// vector <vector<int>> x(20, vector<int> (20)), y(20,vector<int> (20));
/*int counter_1 (int x) {
    if(x == 0) return 0;
    return counter_1(x >> 1) + (x & 1);
}*/

// int Counter(int x)
/*int factorial(int n) {
    if (n > 0) {
        return n * factorial(n - 1);
    } else {
        return 1;
    }
}*/
/*bool pairCompare(const P& firstElof, const P& secondElof)
{
    return firstElof.second > secondElof.second;
}*/

/*long nCr(int n, int r)
{
       if(n==r) return dp[n][r] = 1;
       if(r==0) return dp[n][r] = 1;
       if(r==1) return dp[n][r] = n;
       if(dp[n][r]) return dp[n][r];
       return dp[n][r] = nCr(n-1,r) + nCr(n-1,r-1);
}*/
/*int stoi(std::string str){
int ret;
std::stringstream ss;
ss << str;
ss >> ret;
return ret;
}*/
int main() {
  string s;
  cin >> s;
  int l = s.size();
  int ans = 0;
  FOR(i, 4, l) {
    REP(j, l - i + 1) {
      string f = s.substr(j, i);
      // cout << j << ' ' <<i+j << ' ' << f  << ' ';
      LL ret;
      std::stringstream ss;
      ss << f;
      ss >> ret;
      // cout << ret << endl;
      if (ret % 2019 == 0)
        ans++;
    }
  }
  cout << ans << endl;
}