Problem p02948 (C++)

Buggy submission (status: Runtime Error):
/*
  Warn - Don't change next line else you will get WA verdict. Online Judge is
  configured to give WA if next line is not present. "An ideal problem has no
  test data." Author - Aryan Choudhary (@aryanc403)
*/

#pragma warning(disable : 4996)
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("-ffloat-store")

#include <bits/stdc++.h>
#include <iostream>
#include <stdio.h>
using namespace std;
#define fo(i, n) for (i = 0; i < (n); ++i)
#define repA(i, j, n) for (i = (j); i <= (n); ++i)
#define repD(i, j, n) for (i = (j); i >= (n); --i)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define endl "\n"
typedef long long int lli;
typedef long double mytype;
typedef pair<lli, lli> ii;
typedef vector<ii> vii;
typedef vector<lli> vi;

clock_t time_p = clock();
void aryanc403() {
  time_p = clock() - time_p;
  cerr << "Time Taken : " << (float)(time_p) / CLOCKS_PER_SEC << "\n";
}

#ifdef ARYANC403
#define dbg(...)                                                               \
  {                                                                            \
    cerr << "[ ";                                                              \
    __aryanc403__(#__VA_ARGS__, __VA_ARGS__);                                  \
  }
#undef endl
template <typename Arg1, typename Arg2>
ostream &operator<<(ostream &out, const pair<Arg1, Arg2> &x) {
  return out << "(" << x.X << "," << x.Y << ")";
}

template <typename Arg1>
ostream &operator<<(ostream &out, const vector<Arg1> &a) {
  out << "[";
  for (const auto &x : a)
    out << x << ",";
  return out << "]";
}

template <typename Arg1> ostream &operator<<(ostream &out, const set<Arg1> &a) {
  out << "[";
  for (const auto &x : a)
    out << x << ",";
  return out << "]";
}

template <typename Arg1, typename Arg2>
ostream &operator<<(ostream &out, const map<Arg1, Arg2> &a) {
  out << "[";
  for (const auto &x : a)
    out << x << ",";
  return out << "]";
}

template <typename Arg1> void __aryanc403__(const string name, Arg1 &&arg1) {
  cerr << name << " : " << arg1 << " ] " << endl;
}

template <typename Arg1, typename... Args>
void __aryanc403__(const string names, Arg1 &&arg1, Args &&...args) {
  const string name = names.substr(0, names.find(','));
  cerr << name << " : " << arg1 << " | ";
  __aryanc403__(names.substr(1 + (int)name.size()), args...);
}

#else
#define dbg(args...)
#endif

const lli INF = 0xFFFFFFFFFFFFFFFL;

lli seed;
mt19937 rng(seed = chrono::steady_clock::now().time_since_epoch().count());
inline lli rnd(lli l = 0, lli r = INF) {
  return uniform_int_distribution<lli>(l, r)(rng);
}

class CMP {
public:
  bool operator()(ii a, ii b) // For min priority_queue .
  {
    return !(a.X < b.X || a.X == b.X && a.Y <= b.Y);
  }
};

void add(map<lli, lli> &m, lli x, lli cnt = 1) {
  auto jt = m.find(x);
  if (jt == m.end())
    m.insert({x, cnt});
  else
    jt->Y += cnt;
}

void del(map<lli, lli> &m, lli x, lli cnt = 1) {
  auto jt = m.find(x);
  if (jt->Y <= cnt)
    m.erase(jt);
  else
    jt->Y -= cnt;
}

bool cmp(const ii &a, const ii &b) {
  return a.X > b.X || (a.X == b.X && a.Y > b.Y);
}

const lli mod = 1000000007L;

lli T, n, i, j, k, in, cnt, l, r, u, v, x, y;
lli m;
vii a;
set<lli> s;
// priority_queue < ii , vector < ii > , CMP > pq;// min priority_queue .

int main(void) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  // freopen("txt.in", "r", stdin);
  // freopen("txt.out", "w", stdout);
  // cout<<std::fixed<<std::setprecision(35);
  // cin>>T;while(T--)
  {

    cin >> n >> m;
    a.clear();
    a.reserve(n);

    fo(i, n) {
      cin >> k >> in;
      a.pb({in, m - k});
    }

    repA(i, -1, m + 1) s.insert(i);

    sort(a.begin(), a.end(), cmp);
    dbg(a);
    lli ans = 0;

    for (auto x : a) {
      auto it = s.upper_bound(x.Y);
      --it;
      if (*it == -1)
        continue;
      ans += x.X;
      s.erase(it);
    }

    cout << ans << endl;
  }
  aryanc403();
  return 0;
}

Fixed submission:
/*
  Warn - Don't change next line else you will get WA verdict. Online Judge is
  configured to give WA if next line is not present. "An ideal problem has no
  test data." Author - Aryan Choudhary (@aryanc403)
*/

#pragma warning(disable : 4996)
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("-ffloat-store")

#include <bits/stdc++.h>
#include <iostream>
#include <stdio.h>
using namespace std;
#define fo(i, n) for (i = 0; i < (n); ++i)
#define repA(i, j, n) for (i = (j); i <= (n); ++i)
#define repD(i, j, n) for (i = (j); i >= (n); --i)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define endl "\n"
typedef long long int lli;
typedef long double mytype;
typedef pair<lli, lli> ii;
typedef vector<ii> vii;
typedef vector<lli> vi;

clock_t time_p = clock();
void aryanc403() {
  time_p = clock() - time_p;
  cerr << "Time Taken : " << (float)(time_p) / CLOCKS_PER_SEC << "\n";
}

#ifdef ARYANC403
#define dbg(...)                                                               \
  {                                                                            \
    cerr << "[ ";                                                              \
    __aryanc403__(#__VA_ARGS__, __VA_ARGS__);                                  \
  }
#undef endl
template <typename Arg1, typename Arg2>
ostream &operator<<(ostream &out, const pair<Arg1, Arg2> &x) {
  return out << "(" << x.X << "," << x.Y << ")";
}

template <typename Arg1>
ostream &operator<<(ostream &out, const vector<Arg1> &a) {
  out << "[";
  for (const auto &x : a)
    out << x << ",";
  return out << "]";
}

template <typename Arg1> ostream &operator<<(ostream &out, const set<Arg1> &a) {
  out << "[";
  for (const auto &x : a)
    out << x << ",";
  return out << "]";
}

template <typename Arg1, typename Arg2>
ostream &operator<<(ostream &out, const map<Arg1, Arg2> &a) {
  out << "[";
  for (const auto &x : a)
    out << x << ",";
  return out << "]";
}

template <typename Arg1> void __aryanc403__(const string name, Arg1 &&arg1) {
  cerr << name << " : " << arg1 << " ] " << endl;
}

template <typename Arg1, typename... Args>
void __aryanc403__(const string names, Arg1 &&arg1, Args &&...args) {
  const string name = names.substr(0, names.find(','));
  cerr << name << " : " << arg1 << " | ";
  __aryanc403__(names.substr(1 + (int)name.size()), args...);
}

#else
#define dbg(args...)
#endif

const lli INF = 0xFFFFFFFFFFFFFFFL;

lli seed;
mt19937 rng(seed = chrono::steady_clock::now().time_since_epoch().count());
inline lli rnd(lli l = 0, lli r = INF) {
  return uniform_int_distribution<lli>(l, r)(rng);
}

class CMP {
public:
  bool operator()(ii a, ii b) // For min priority_queue .
  {
    return !(a.X < b.X || a.X == b.X && a.Y <= b.Y);
  }
};

void add(map<lli, lli> &m, lli x, lli cnt = 1) {
  auto jt = m.find(x);
  if (jt == m.end())
    m.insert({x, cnt});
  else
    jt->Y += cnt;
}

void del(map<lli, lli> &m, lli x, lli cnt = 1) {
  auto jt = m.find(x);
  if (jt->Y <= cnt)
    m.erase(jt);
  else
    jt->Y -= cnt;
}

bool cmp(const ii &a, const ii &b) {
  return a.X > b.X || (a.X == b.X && a.Y > b.Y);
}

const lli mod = 1000000007L;

lli T, n, i, j, k, in, cnt, l, r, u, v, x, y;
lli m;
vii a;
set<lli> s;
// priority_queue < ii , vector < ii > , CMP > pq;// min priority_queue .

int main(void) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  // freopen("txt.in", "r", stdin);
  // freopen("txt.out", "w", stdout);
  // cout<<std::fixed<<std::setprecision(35);
  // cin>>T;while(T--)
  {

    cin >> n >> m;
    a.clear();
    a.reserve(n);

    fo(i, n) {
      cin >> k >> in;
      if (m - k < 0)
        continue;
      a.pb({in, m - k});
    }

    repA(i, -1, m + 1) s.insert(i);

    sort(a.begin(), a.end(), cmp);
    dbg(a);
    lli ans = 0;

    for (auto x : a) {
      auto it = s.upper_bound(x.Y);
      --it;
      if (*it == -1)
        continue;
      ans += x.X;
      s.erase(it);
    }

    cout << ans << endl;
  }
  aryanc403();
  return 0;
}