Problem p02888 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <unordered_map>
#include <vector>

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

using namespace std;

#define rep(i, n) for (int i = 0, i##_len = (n); i < i##_len; ++i)
#define repx(i, s, d, e) for (int i = s, i##_end = (e); i < i##_end; i += d)
#define repxr(i, s, d, e) for (int i = s, i##_end = (e); i > i##_end; i += d)
#define rept(n)                                                                \
  for (int ___i___ = 0, i##_len = (n); ___i___ < i##_len; ++___i___)
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define ZERO(a) memset(a, 0, sizeof(a))
#define BIT(n) (1LL << (n))
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());
#define CEIL(x, y) (((x) + (y)-1) / (y))

// vector
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
// pair
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  os << "(" << pair_var.first << ", " << pair_var.second << ")";
  return os;
}
// vector
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  os << "{";
  for (int i = 0; i < vec.size(); i++) {
    os << vec[i] << (i + 1 == vec.size() ? "" : ", ");
  }
  os << "}";
  return os;
}
// map
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  os << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      os << ", ";
    itr--;
  }
  os << "}";
  return os;
}
// set
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  os << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      os << ", ";
    itr--;
  }
  os << "}";
  return os;
}
#define DUMPOUT cout
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0) {
    DUMPOUT << ", ";
  }
  dump_func(std::move(tail)...);
}
#ifdef LOCAL_
#define dump(...)                                                              \
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \
          << "    ",                                                           \
      dump_func(__VA_ARGS__)
#else
#define dump(...)
#endif

typedef long long int lli;
typedef pair<int, int> ii;
typedef priority_queue<int, vector<int>, greater<int>> heapq;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
struct aaa {
  aaa() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(20);
  };
} aaaaaaa;

// #define int long long int
// struct S{
//     bool operator<(const S& x) const {
//         return ;
//     }
// };
signed main() {
  int N;
  cin >> N;
  int L[1001];
  rep(i, N) { cin >> L[i]; }
  sort(L, L + N);

  int ans = 0;
  rep(i, N) {
    repx(j, i + 1, 1, N) {
      int lK = lower_bound(L, L + N, L[j] - L[i]) - L;
      lK = max(lK, j);

      int uK = upper_bound(L, L + N, L[i] + L[j] - 1) - L;

      if (uK <= lK)
        continue;

      ans += uK - lK - 1;
      dump(i, j, L[i], L[j], uK, lK, ans);
    }
  }

  cout << ans << endl;
  return 0;
}


Fixed submission:
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <unordered_map>
#include <vector>

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

using namespace std;

#define rep(i, n) for (int i = 0, i##_len = (n); i < i##_len; ++i)
#define repx(i, s, d, e) for (int i = s, i##_end = (e); i < i##_end; i += d)
#define repxr(i, s, d, e) for (int i = s, i##_end = (e); i > i##_end; i += d)
#define rept(n)                                                                \
  for (int ___i___ = 0, i##_len = (n); ___i___ < i##_len; ++___i___)
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define ZERO(a) memset(a, 0, sizeof(a))
#define BIT(n) (1LL << (n))
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());
#define CEIL(x, y) (((x) + (y)-1) / (y))

// vector
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
// pair
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  os << "(" << pair_var.first << ", " << pair_var.second << ")";
  return os;
}
// vector
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  os << "{";
  for (int i = 0; i < vec.size(); i++) {
    os << vec[i] << (i + 1 == vec.size() ? "" : ", ");
  }
  os << "}";
  return os;
}
// map
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  os << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      os << ", ";
    itr--;
  }
  os << "}";
  return os;
}
// set
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  os << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      os << ", ";
    itr--;
  }
  os << "}";
  return os;
}
#define DUMPOUT cout
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0) {
    DUMPOUT << ", ";
  }
  dump_func(std::move(tail)...);
}
#ifdef LOCAL_
#define dump(...)                                                              \
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \
          << "    ",                                                           \
      dump_func(__VA_ARGS__)
#else
#define dump(...)
#endif

typedef long long int lli;
typedef pair<int, int> ii;
typedef priority_queue<int, vector<int>, greater<int>> heapq;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
struct aaa {
  aaa() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(20);
  };
} aaaaaaa;

// #define int long long int
// struct S{
//     bool operator<(const S& x) const {
//         return ;
//     }
// };
signed main() {
  int N;
  cin >> N;
  int L[2001];
  rep(i, N) { cin >> L[i]; }
  sort(L, L + N);

  int ans = 0;
  rep(i, N) {
    repx(j, i + 1, 1, N) {
      int lK = lower_bound(L, L + N, L[j] - L[i]) - L;
      lK = max(lK, j);

      int uK = upper_bound(L, L + N, L[i] + L[j] - 1) - L;

      if (uK <= lK)
        continue;

      ans += uK - lK - 1;
      dump(i, j, L[i], L[j], uK, lK, ans);
    }
  }

  cout << ans << endl;
  return 0;
}