Problem p02888 (C++)

Buggy submission (status: Time Limit Exceeded):
#ifndef LOCAL
#pragma GCC optimize("O3")
#endif
#include "bits/stdc++.h"
using namespace std;
#define sim template <class c
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \
  sim > typename enable_if<sizeof dud<c>(0) x 1, debug &>::type operator<<(    \
            c i) {
sim > struct rge {
  c b, e;
};
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) cerr << boolalpha << i;
  ris;
} eni(==) ris << range(begin(i), end(i));
}
sim, class b dor(pair<b, c> d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
  sim dor(const c &) { ris; }
#endif
}
;
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define fastio                                                                 \
  ios_base::sync_with_stdio(false);                                            \
  cin.tie(0);
using ll = long long;
const ll INF = 1e10 + 10;

int main() {
  fastio ll n;
  cin >> n;

  vector<ll> v(n);
  for (ll i = 0; i < n; i++) {
    cin >> v[i];
  }
  ll cnt = 0;
  for (ll i = 0; i < n; i++) {
    for (ll j = i + 1; j < n; j++) {
      for (ll c = j + 1; c < n; c++) {
        if (v[i] < v[j] + v[c] && v[j] < v[c] + v[i] && v[c] < v[i] + v[j])
          cnt++;
      }
    }
  }
  cout << cnt << endl;

  return 0;
}

Fixed submission:
#ifndef LOCAL
#pragma GCC optimize("O3")
#endif
#include "bits/stdc++.h"
using namespace std;
#define sim template <class c
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \
  sim > typename enable_if<sizeof dud<c>(0) x 1, debug &>::type operator<<(    \
            c i) {
sim > struct rge {
  c b, e;
};
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) cerr << boolalpha << i;
  ris;
} eni(==) ris << range(begin(i), end(i));
}
sim, class b dor(pair<b, c> d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
  sim dor(const c &) { ris; }
#endif
}
;
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define fastio                                                                 \
  ios_base::sync_with_stdio(false);                                            \
  cin.tie(0);
using ll = long long;
const ll INF = 1e10 + 10;

int main() {
  fastio ll n;
  cin >> n;

  vector<ll> v(n);
  for (ll i = 0; i < n; i++) {
    cin >> v[i];
  }
  sort(v.begin(), v.end());
  ll cnt = 0;
  for (ll i = 0; i < n; i++) {
    for (ll j = i + 1; j < n; j++) {
      for (ll c = j + 1; c < n; c++) {
        if (v[i] < v[j] + v[c] && v[j] < v[c] + v[i] && v[c] < v[i] + v[j])
          cnt++;
      }
    }
  }
  cout << cnt << endl;

  return 0;
}