Problem p03476 (C++)

Buggy submission (status: Runtime Error):
#pragma GCC optimize("O3")

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include <prettyprint.hpp>
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]: ", d_err(__VA_ARGS__);
#else
#define debug(...) 83;
#endif

void d_err() { cerr << endl; }

template <typename H, typename... T> void d_err(H h, T... t) {
  cerr << h << " ";
  d_err(t...);
}

template <typename T> void print(T x) { cout << x << "\n"; }

#define ALL(x) (x).begin(), (x).end()
#define FOR(i, m, n) for (int i = (m); i < (n); ++i)
#define REVFOR(i, m, n) for (int i = (n - 1); i >= (m); --i)
#define REP(i, n) FOR(i, 0, n)
#define REVREP(i, n) REVFOR(i, 0, n)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define bcnt __builtin_popcountll

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<ll, ll> Pll;
typedef pair<int, int> Pin;

ll INF = 1e16;
int inf = 1e9;
ll MOD = 1e9 + 7;

int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(20);

  int n = 10000;
  vector<int> prime;
  vector<bool> v(n + 1, false);
  for (int i = 2; i <= n; ++i) {
    if (v[i])
      continue;
    prime.pb(i);

    for (int j = i; j <= n; j += i)
      v[j] = true;
  }

  vector<int> k;
  for (auto &e : prime) {
    ll cur = (e + 1) / 2;
    auto it = find(ALL(prime), cur);
    if (it != prime.end())
      k.pb(e);
  }

  vector<int> s(n + 2, 0);

  int j = 0;
  REP(i, s.size() - 1) {
    if (j < k.size() && i == k[j])
      s[i] += 1, j++;
    s[i + 1] = s[i];
  }

  int q;
  cin >> q;
  REP(i, q) {
    int l, r;
    cin >> l >> r;
    print(s[r] - s[l - 1]);
  }
}

Fixed submission:
#pragma GCC optimize("O3")

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include <prettyprint.hpp>
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]: ", d_err(__VA_ARGS__);
#else
#define debug(...) 83;
#endif

void d_err() { cerr << endl; }

template <typename H, typename... T> void d_err(H h, T... t) {
  cerr << h << " ";
  d_err(t...);
}

template <typename T> void print(T x) { cout << x << "\n"; }

#define ALL(x) (x).begin(), (x).end()
#define FOR(i, m, n) for (int i = (m); i < (n); ++i)
#define REVFOR(i, m, n) for (int i = (n - 1); i >= (m); --i)
#define REP(i, n) FOR(i, 0, n)
#define REVREP(i, n) REVFOR(i, 0, n)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define bcnt __builtin_popcountll

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<ll, ll> Pll;
typedef pair<int, int> Pin;

ll INF = 1e16;
int inf = 1e9;
ll MOD = 1e9 + 7;

int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(20);

  int n = 100000;
  vector<int> prime;
  vector<bool> v(n + 1, false);
  for (int i = 2; i <= n; ++i) {
    if (v[i])
      continue;
    prime.pb(i);

    for (int j = i; j <= n; j += i)
      v[j] = true;
  }

  vector<int> k;
  for (auto &e : prime) {
    ll cur = (e + 1) / 2;
    auto it = find(ALL(prime), cur);
    if (it != prime.end())
      k.pb(e);
  }

  vector<int> s(n + 2, 0);

  int j = 0;
  REP(i, s.size() - 1) {
    if (j < k.size() && i == k[j])
      s[i] += 1, j++;
    s[i + 1] = s[i];
  }

  int q;
  cin >> q;
  REP(i, q) {
    int l, r;
    cin >> l >> r;
    print(s[r] - s[l - 1]);
  }
}