Problem p02948 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <bits/stdc++.h>
#include <cmath>
#include <string>
#include <vector>

#define fast                                                                   \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define int long long int
#define mod 1000000007
#define inf 1e18 + 42
#define endl "\n"
#define pi 3.1415926535897932384626433832795028841971693993751058
#define maxn 100005

#define out1(a) cout << #a << " " << a << endl
#define out2(a, b) cout << #a << " " << a << " " << #b << " " << b << endl
#define out3(a, b, c)                                                          \
  cout << #a << " " << a << " " << #b << " " << b << " " << #c << " " << c     \
       << endl

#define rep(i, a, b) for (int i = a; i < b; i++)
#define repr(i, a, b) for (int i = a; i >= b; i--)
#define fori(it, A) for (auto it = A.begin(); it != A.end(); it++)

#define ft first
#define sd second
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(), (x).end()
#define zero(x) memset(x, 0, sizeof(x));

using namespace std;

int binpow(int a, int b) {
  int res = 1;
  while (b > 0) {
    if (b & 1)
      res = res * a;
    a = a * a;
    b >>= 1;
  }
  return res;
}

// START OF CODE ->->->->->->->

void solve() {
  int n, m;
  cin >> n >> m;

  // map< int,priority_queue<int> > p;
  vector<pair<int, int>> p;

  rep(i, 0, n) {
    int a, b;
    cin >> a >> b;

    if (a <= m) {
      // continue;
      p.pb(mp(a, b));
    }
  }
  int ans = 0;
  sort(all(p));
  priority_queue<int> s;
  int idx = 0;
  rep(i, 1, m + 1) {
    while (idx < n && p[idx].ft <= i) {
      s.push(p[idx].sd);
      idx++;
    }

    if (!s.empty()) {
      ans += s.top();
      s.pop();
    }
  }
  cout << ans << endl;
}

// END OF CODE ->->->->->->->->

signed main() {
  fast;
  int t = 1;
  // cin>>t;

  while (t--) {
    solve();
  }
  return 0;
}


Fixed submission:
#include <algorithm>
#include <bits/stdc++.h>
#include <cmath>
#include <string>
#include <vector>

#define fast                                                                   \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define int long long int
#define mod 1000000007
#define inf 1e18 + 42
#define endl "\n"
#define pi 3.1415926535897932384626433832795028841971693993751058
#define maxn 100005

#define out1(a) cout << #a << " " << a << endl
#define out2(a, b) cout << #a << " " << a << " " << #b << " " << b << endl
#define out3(a, b, c)                                                          \
  cout << #a << " " << a << " " << #b << " " << b << " " << #c << " " << c     \
       << endl

#define rep(i, a, b) for (int i = a; i < b; i++)
#define repr(i, a, b) for (int i = a; i >= b; i--)
#define fori(it, A) for (auto it = A.begin(); it != A.end(); it++)

#define ft first
#define sd second
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(), (x).end()
#define zero(x) memset(x, 0, sizeof(x));

using namespace std;

int binpow(int a, int b) {
  int res = 1;
  while (b > 0) {
    if (b & 1)
      res = res * a;
    a = a * a;
    b >>= 1;
  }
  return res;
}

// START OF CODE ->->->->->->->

void solve() {
  int n, m;
  cin >> n >> m;

  // map< int,priority_queue<int> > p;
  vector<pair<int, int>> p;

  rep(i, 0, n) {
    int a, b;
    cin >> a >> b;

    p.pb(mp(a, b));
  }
  int ans = 0;
  sort(all(p));
  priority_queue<int> s;
  int idx = 0;
  rep(i, 1, m + 1) {
    while (idx < n && p[idx].ft <= i) {
      s.push(p[idx].sd);
      idx++;
    }

    if (!s.empty()) {
      ans += s.top();
      s.pop();
    }
  }
  cout << ans << endl;
}

// END OF CODE ->->->->->->->->

signed main() {
  fast;
  int t = 1;
  // cin>>t;

  while (t--) {
    solve();
  }
  return 0;
}