Problem:
Pair of Primes
We arrange the numbers between 1 and N (1 <= N <= 10000) in increasing
order and decreasing order like this:
1 2 3 4 5 6 7 8 9 . . . N
N . . . 9 8 7 6 5 4 3 2 1
Two numbers faced each other form a pair. Your task is to compute the number of pairs P such that both
numbers in the pairs are prime.
Input
Input contains several test cases. Each test case consists of an integer N in
one line.
Output
For each line of input, output P .
Sample Input
1
4
7
51
Output for the Sample Input
0
2
2
6

Submitted solutions:

code_snippet: #include <iostream>
#include <string.h>
#include <stdio.h>
#include <vector>
#include <list>
#include <math.h>
#include <algorithm>
using namespace std;

pair<int, int> pii[10005];
int N, answer;
bool isPrime(int n) {
    if (n == 1) return 0;
    if (n == 2) return 1;
    for (int i = 2; i <= sqrt(n); i ++)
        if (n % i == 0) return false;
    return true;
}
int main() {
    while (scanf("%d", &N) != EOF) {
        answer = 0;
        for (int i = 1; i <= N; i ++) {
            pii[i].first = i;
            pii[i].second = N - i + 1;
        }
        for (int i = 1; i <= N; i ++) {
            if (isPrime(pii[i].first) && isPrime(pii[i].second))
                answer ++;
        }
        cout << answer << endl;
    }
    return 0;
}
accuracy: 1
time_ms: 80
memory_kb: 3312
final_rank: 10

code_snippet: #line 1 "/home/maspy/compro/library/my_template.hpp"
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using pi = pair<ll, ll>;
using vi = vector<ll>;
using u32 = unsigned int;
using u64 = unsigned long long;
using i128 = __int128;

template <class T>
using vc = vector<T>;
template <class T>
using vvc = vector<vc<T>>;
template <class T>
using vvvc = vector<vvc<T>>;
template <class T>
using vvvvc = vector<vvvc<T>>;
template <class T>
using vvvvvc = vector<vvvvc<T>>;
template <class T>
using pq = priority_queue<T>;
template <class T>
using pqg = priority_queue<T, vector<T>, greater<T>>;

#define vec(type, name, ...) vector<type> name(__VA_ARGS__)
#define vv(type, name, h, ...) \
  vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define vvv(type, name, h, w, ...)   \
  vector<vector<vector<type>>> name( \
      h, vector<vector<type>>(w, vector<type>(__VA_ARGS__)))
#define vvvv(type, name, a, b, c, ...)       \
  vector<vector<vector<vector<type>>>> name( \
      a, vector<vector<vector<type>>>(       \
             b, vector<vector<type>>(c, vector<type>(__VA_ARGS__))))

// https://trap.jp/post/1224/
#define FOR1(a) for (ll _ = 0; _ < ll(a); ++_)
#define FOR2(i, a) for (ll i = 0; i < ll(a); ++i)
#define FOR3(i, a, b) for (ll i = a; i < ll(b); ++i)
#define FOR4(i, a, b, c) for (ll i = a; i < ll(b); i += (c))
#define FOR1_R(a) for (ll i = (a)-1; i >= ll(0); --i)
#define FOR2_R(i, a) for (ll i = (a)-1; i >= ll(0); --i)
#define FOR3_R(i, a, b) for (ll i = (b)-1; i >= ll(a); --i)
#define FOR4_R(i, a, b, c) for (ll i = (b)-1; i >= ll(a); i -= (c))
#define overload4(a, b, c, d, e, ...) e
#define FOR(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define FOR_R(...) \
  overload4(__VA_ARGS__, FOR4_R, FOR3_R, FOR2_R, FOR1_R)(__VA_ARGS__)

#define FOR_subset(t, s) for (ll t = s; t >= 0; t = (t == 0 ? -1 : (t - 1) & s))
#define all(x) x.begin(), x.end()
#define len(x) ll(x.size())
#define elif else if

#define eb emplace_back
#define mp make_pair
#define mt make_tuple
#define fi first
#define se second

#define stoi stoll

ll SUM(vector<int> &A) {
  ll sum = 0;
  for (auto &&a: A) sum += a;
  return sum;
}

template <typename T>
T SUM(vector<T> &A) {
  T sum = T(0);
  for (auto &&a: A) sum += a;
  return sum;
}

#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))
#define LB(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define UB(c, x) distance((c).begin(), upper_bound(all(c), (x)))
#define UNIQUE(x) sort(all(x)), x.erase(unique(all(x)), x.end())

int popcnt(int x) { return __builtin_popcount(x); }
int popcnt(u32 x) { return __builtin_popcount(x); }
int popcnt(ll x) { return __builtin_popcountll(x); }
int popcnt(u64 x) { return __builtin_popcountll(x); }
// (0, 1, 2, 3, 4) -> (-1, 0, 1, 1, 2)
int topbit(int x) { return (x == 0 ? -1 : 31 - __builtin_clz(x)); }
int topbit(u32 x) { return (x == 0 ? -1 : 31 - __builtin_clz(x)); }
int topbit(ll x) { return (x == 0 ? -1 : 63 - __builtin_clzll(x)); }
int topbit(u64 x) { return (x == 0 ? -1 : 63 - __builtin_clzll(x)); }
// (0, 1, 2, 3, 4) -> (-1, 0, 1, 0, 2)
int lowbit(int x) { return (x == 0 ? -1 : __builtin_ctz(x)); }
int lowbit(u32 x) { return (x == 0 ? -1 : __builtin_ctz(x)); }
int lowbit(ll x) { return (x == 0 ? -1 : __builtin_ctzll(x)); }
int lowbit(u64 x) { return (x == 0 ? -1 : __builtin_ctzll(x)); }

template <typename T, typename U>
T ceil(T x, U y) {
  return (x > 0 ? (x + y - 1) / y : x / y);
}

template <typename T, typename U>
T floor(T x, U y) {
  return (x > 0 ? x / y : (x - y + 1) / y);
}

template <typename T, typename U>
pair<T, T> divmod(T x, U y) {
  T q = floor(x, y);
  return {q, x - q * y};
}

ll binary_search(function<bool(ll)> check, ll ok, ll ng) {
  assert(check(ok));
  while (abs(ok - ng) > 1) {
    auto x = (ng + ok) / 2;
    if (check(x))
      ok = x;
    else
      ng = x;
  }
  return ok;
}

template <typename F>
double binary_search_real(F check, double ok, double ng, int iter = 100) {
  FOR(iter) {
    double x = (ok + ng) / 2;
    if (check(x)) {
      ok = x;
    } else {
      ng = x;
    }
  }
  return (ok + ng) / 2;
}

template <class T, class S>
inline bool chmax(T &a, const S &b) {
  return (a < b ? a = b, 1 : 0);
}
template <class T, class S>
inline bool chmin(T &a, const S &b) {
  return (a > b ? a = b, 1 : 0);
}

vi s_to_vi(const string &S, char first_char) {
  vi A(S.size());
  FOR(i, S.size()) { A[i] = S[i] - first_char; }
  return A;
}

template <typename T>
vector<T> cumsum(vector<T> &A, int off = 1) {
  int N = A.size();
  vector<T> B(N + 1);
  FOR(i, N) { B[i + 1] = B[i] + A[i]; }
  if (off == 0) B.erase(B.begin());
  return B;
}

template <typename CNT, typename T>
vc<CNT> bincount(const vc<T> &A, int size) {
  vc<CNT> C(size);
  for (auto &&x: A) { ++C[x]; }
  return C;
}

template <typename T>
vector<int> argsort(const vector<T> &A) {
  // stable
  vector<int> ids(A.size());
  iota(all(ids), 0);
  sort(all(ids),
       [&](int i, int j) { return A[i] < A[j] || (A[i] == A[j] && i < j); });
  return ids;
}

// A[I[0]], A[I[1]], ...
template <typename T>
vc<T> rearrange(const vc<T> &A, const vc<int> &I) {
  int n = len(I);
  vc<T> B(n);
  FOR(i, n) B[i] = A[I[i]];
  return B;
}
#line 1 "/home/maspy/compro/library/other/io.hpp"
// based on yosupo's fastio
#include <unistd.h>

namespace detail {
template <typename T, decltype(&T::is_modint) = &T::is_modint>
std::true_type check_value(int);
template <typename T>
std::false_type check_value(long);
} // namespace detail

template <typename T>
struct is_modint : decltype(detail::check_value<T>(0)) {};
template <typename T>
using is_modint_t = enable_if_t<is_modint<T>::value>;
template <typename T>
using is_not_modint_t = enable_if_t<!is_modint<T>::value>;

struct Scanner {
  FILE *fp;
  char line[(1 << 15) + 1];
  size_t st = 0, ed = 0;
  void reread() {
    memmove(line, line + st, ed - st);
    ed -= st;
    st = 0;
    ed += fread(line + ed, 1, (1 << 15) - ed, fp);
    line[ed] = '\0';
  }
  bool succ() {
    while (true) {
      if (st == ed) {
        reread();
        if (st == ed) return false;
      }
      while (st != ed && isspace(line[st])) st++;
      if (st != ed) break;
    }
    if (ed - st <= 50) {
      bool sep = false;
      for (size_t i = st; i < ed; i++) {
        if (isspace(line[i])) {
          sep = true;
          break;
        }
      }
      if (!sep) reread();
    }
    return true;
  }
  template <class T, enable_if_t<is_same<T, string>::value, int> = 0>
  bool read_single(T &ref) {
    if (!succ()) return false;
    while (true) {
      size_t sz = 0;
      while (st + sz < ed && !isspace(line[st + sz])) sz++;
      ref.append(line + st, sz);
      st += sz;
      if (!sz || st != ed) break;
      reread();
    }
    return true;
  }
  template <class T, enable_if_t<is_integral<T>::value, int> = 0>
  bool read_single(T &ref) {
    if (!succ()) return false;
    bool neg = false;
    if (line[st] == '-') {
      neg = true;
      st++;
    }
    ref = T(0);
    while (isdigit(line[st])) { ref = 10 * ref + (line[st++] & 0xf); }
    if (neg) ref = -ref;
    return true;
  }
  template <class T, is_modint_t<T> * = nullptr>
  bool read_single(T &ref) {
    long long val = 0;
    bool f = read_single(val);
    ref = T(val);
    return f;
  }
  bool read_single(double &ref) {
    string s;
    if (!read_single(s)) return false;
    ref = std::stod(s);
    return true;
  }
  bool read_single(char &ref) {
    string s;
    if (!read_single(s) || s.size() != 1) return false;
    ref = s[0];
    return true;
  }
  template <class T>
  bool read_single(vector<T> &ref) {
    for (auto &d: ref) {
      if (!read_single(d)) return false;
    }
    return true;
  }
  template <class T, class U>
  bool read_single(pair<T, U> &p) {
    return (read_single(p.first) && read_single(p.second));
  }
  template <class A, class B, class C>
  bool read_single(tuple<A, B, C> &p) {
    return (read_single(get<0>(p)) && read_single(get<1>(p))
            && read_single(get<2>(p)));
  }
  template <class A, class B, class C, class D>
  bool read_single(tuple<A, B, C, D> &p) {
    return (read_single(get<0>(p)) && read_single(get<1>(p))
            && read_single(get<2>(p)) && read_single(get<3>(p)));
  }
  void read() {}
  template <class H, class... T>
  void read(H &h, T &... t) {
    bool f = read_single(h);
    assert(f);
    read(t...);
  }
  Scanner(FILE *fp) : fp(fp) {}
};

struct Printer {
  Printer(FILE *_fp) : fp(_fp) {}
  ~Printer() { flush(); }

  static constexpr size_t SIZE = 1 << 15;
  FILE *fp;
  char line[SIZE], small[50];
  size_t pos = 0;
  void flush() {
    fwrite(line, 1, pos, fp);
    pos = 0;
  }
  void write(const char &val) {
    if (pos == SIZE) flush();
    line[pos++] = val;
  }
  template <class T, enable_if_t<is_integral<T>::value, int> = 0>
  void write(T val) {
    if (pos > (1 << 15) - 50) flush();
    if (val == 0) {
      write('0');
      return;
    }
    if (val < 0) {
      write('-');
      val = -val; // todo min
    }
    size_t len = 0;
    while (val) {
      small[len++] = char(0x30 | (val % 10));
      val /= 10;
    }
    for (size_t i = 0; i < len; i++) { line[pos + i] = small[len - 1 - i]; }
    pos += len;
  }
  void write(const string &s) {
    for (char c: s) write(c);
  }
  void write(const char *s) {
    size_t len = strlen(s);
    for (size_t i = 0; i < len; i++) write(s[i]);
  }
  void write(const double &x) {
    ostringstream oss;
    oss << fixed << setprecision(15) << x;
    string s = oss.str();
    write(s);
  }
  void write(const long double &x) {
    ostringstream oss;
    oss << fixed << setprecision(15) << x;
    string s = oss.str();
    write(s);
  }
  template <class T, is_modint_t<T> * = nullptr>
  void write(T &ref) {
    write(ref.val);
  }
  template <class T>
  void write(const vector<T> &val) {
    auto n = val.size();
    for (size_t i = 0; i < n; i++) {
      if (i) write(' ');
      write(val[i]);
    }
  }
  template <class T, class U>
  void write(const pair<T, U> &val) {
    write(val.first);
    write(' ');
    write(val.second);
  }
  template <class A, class B, class C>
  void write(const tuple<A, B, C> &val) {
    auto &[a, b, c] = val;
    write(a), write(' '), write(b), write(' '), write(c);
  }
  template <class A, class B, class C, class D>
  void write(const tuple<A, B, C, D> &val) {
    auto &[a, b, c, d] = val;
    write(a), write(' '), write(b), write(' '), write(c), write(' '), write(d);
  }
  template <class A, class B, class C, class D, class E>
  void write(const tuple<A, B, C, D, E> &val) {
    auto &[a, b, c, d, e] = val;
    write(a), write(' '), write(b), write(' '), write(c), write(' '), write(d), write(' '), write(e);
  }
  template <class A, class B, class C, class D, class E, class F>
  void write(const tuple<A, B, C, D, E, F> &val) {
    auto &[a, b, c, d, e, f] = val;
    write(a), write(' '), write(b), write(' '), write(c), write(' '), write(d), write(' '), write(e), write(' '), write(f);
  }
  template <class T, size_t S>
  void write(const array<T, S> &val) {
    auto n = val.size();
    for (size_t i = 0; i < n; i++) {
      if (i) write(' ');
      write(val[i]);
    }
  }
  void write(i128 val) {
    string s;
    bool negative = 0;
    if(val < 0){
      negative = 1;
      val = -val;
    }
    while (val) {
      s += '0' + int(val % 10);
      val /= 10;
    }
    if(negative) s += "-";
    reverse(all(s));
    if (len(s) == 0) s = "0";
    write(s);
  }
};

Scanner scanner = Scanner(stdin);
Printer printer = Printer(stdout);

void flush() { printer.flush(); }
void print() { printer.write('\n'); }
template <class Head, class... Tail>
void print(Head &&head, Tail &&... tail) {
  printer.write(head);
  if (sizeof...(Tail)) printer.write(' ');
  print(forward<Tail>(tail)...);
}

void read() {}
template <class Head, class... Tail>
void read(Head &head, Tail &... tail) {
  scanner.read(head);
  read(tail...);
}

#define INT(...)   \
  int __VA_ARGS__; \
  read(__VA_ARGS__)
#define LL(...)   \
  ll __VA_ARGS__; \
  read(__VA_ARGS__)
#define STR(...)      \
  string __VA_ARGS__; \
  read(__VA_ARGS__)
#define CHAR(...)      \
  char __VA_ARGS__; \
  read(__VA_ARGS__)
#define DBL(...)      \
  double __VA_ARGS__; \
  read(__VA_ARGS__)

#define VEC(type, name, size) \
  vector<type> name(size);    \
  read(name)
#define VV(type, name, h, w)                     \
  vector<vector<type>> name(h, vector<type>(w)); \
  read(name)

void YES(bool t = 1) { print(t ? "YES" : "NO"); }
void NO(bool t = 1) { YES(!t); }
void Yes(bool t = 1) { print(t ? "Yes" : "No"); }
void No(bool t = 1) { Yes(!t); }
void yes(bool t = 1) { print(t ? "yes" : "no"); }
void no(bool t = 1) { yes(!t); }
#line 2 "/home/maspy/compro/library/nt/primetest.hpp"
struct m64 {
  using i64 = int64_t;
  using u64 = uint64_t;
  using u128 = __uint128_t;

  inline static u64 m, r, n2; // r * m = -1 (mod 1<<64), n2 = 1<<128 (mod m)
  static void set_mod(u64 m) {
    assert(m < (1ull << 62));
    assert((m & 1) == 1);
    m64::m = m;
    n2 = -u128(m) % m;
    r = m;
    FOR(_, 5) r *= 2 - m * r;
    r = -r;
    assert(r * m == -1ull);
  }
  static u64 reduce(u128 b) { return (b + u128(u64(b) * r) * m) >> 64; }

  u64 x;
  m64() : x(0) {}
  m64(u64 x) : x(reduce(u128(x) * n2)){};
  u64 val() const {
    u64 y = reduce(x);
    return y >= m ? y - m : y;
  }
  m64 &operator+=(m64 y) {
    x += y.x - (m << 1);
    x = (i64(x) < 0 ? x + (m << 1) : x);
    return *this;
  }
  m64 &operator-=(m64 y) {
    x -= y.x;
    x = (i64(x) < 0 ? x + (m << 1) : x);
    return *this;
  }
  m64 &operator*=(m64 y) {
    x = reduce(u128(x) * y.x);
    return *this;
  }
  m64 operator+(m64 y) const { return m64(*this) += y; }
  m64 operator-(m64 y) const { return m64(*this) -= y; }
  m64 operator*(m64 y) const { return m64(*this) *= y; }
  bool operator==(m64 y) const {
    return (x >= m ? x - m : x) == (y.x >= m ? y.x - m : y.x);
  }
  bool operator!=(m64 y) const { return not operator==(y); }
  m64 pow(u64 n) const {
    m64 y = 1, z = *this;
    for (; n; n >>= 1, z *= z)
      if (n & 1) y *= z;
    return y;
  }
};

bool primetest(const uint64_t x) {
  using u64 = uint64_t;
  if (x == 2 or x == 3 or x == 5 or x == 7) return true;
  if (x % 2 == 0 or x % 3 == 0 or x % 5 == 0 or x % 7 == 0) return false;
  if (x < 121) return x > 1;
  const u64 d = (x - 1) >> __builtin_ctzll(x - 1);
  m64::set_mod(x);
  const m64 one(1), minus_one(x - 1);
  auto ok = [&](u64 a) {
    auto y = m64(a).pow(d);
    u64 t = d;
    while (y != one and y != minus_one and t != x - 1) y *= y, t <<= 1;
    if (y != minus_one and t % 2 == 0) return false;
    return true;
  };
  if (x < (1ull << 32)) {
    for (u64 a: {2, 7, 61})
      if (not ok(a)) return false;
  } else {
    for (u64 a: {2, 325, 9375, 28178, 450775, 9780504, 1795265022}) {
      if (x <= a) return true;
      if (not ok(a)) return false;
    }
  }
  return true;
}
#line 4 "main.cpp"

void solve() {
  ll N;
  while (cin >> N) {
    ll ANS = 0;
    FOR(x, 1, N + 1) {
      if (primetest(x) && primetest(N + 1 - x)) ++ANS;
    }
    print(ANS);
  }
}

signed main() {
  cout << fixed << setprecision(15);

  ll T = 1;
  // LL(T);
  FOR(T) solve();

  return 0;
}
accuracy: 1
time_ms: 100
memory_kb: 3188
final_rank: 12

code_snippet: #include <iostream>
#define MAX 10000
using namespace std;

int P[MAX];

bool isprime(int n){
    if (n == 2) return true;
    if (n % 2 == 0 || n == 1) return false;
    for ( int i = 3; i * i <= n; i += 2 ) {
        if (n % i == 0) return false;
    }
    return true;
}

int main(void) {
    int n;
    while(cin >> n){
        int cnt = 0;
        for(int i = 1; i <= n; i++){
            if(isprime(i) && isprime(n + 1 - i)) cnt++;
        }
        cout << cnt << endl;
    }
    return 0;
}
accuracy: 1
time_ms: 50
memory_kb: 3076
final_rank: 7

code_snippet: #define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
using namespace std;
#ifndef FAST_IO
 #define IOS ios_base::sync_with_stdio(false);cin.tie(nullptr);
#endif

#define int long long
#define FILE_IO freopen("input.txt","r",stdin)/#define int long long
#define f first
#define s second
#define endl '\n'
#define all(c) c.begin(),c.end()
#define bp __builtin_popcount
#define debug(x) cerr << #x << " = " << x << endl;

const int MOD = 1e9 + 7;
const int INF = 1e18;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T>void print(T t){for (auto &it : t) cout << it << " ";}
inline int powerexp(int a, int b, int m = MOD){ int res = 1;while(b){if(b&1)res = res * a % m;a = a * a % m,b >>= 1;}return res % m;}
inline int modinv(int a){ return powerexp(a,MOD-2,MOD);}
inline int lcm(int a, int b){ int g = __gcd(a,b);return a/g*b;}
inline int add(int x, int y){ x += y; if (x >= MOD) x -=  MOD; return x;}
inline int mul(int x, int y){ return (x * 1ll * y) % MOD;}
inline int sub(int x, int y){ x -= y; if (x<0) x += MOD; return x ;}

//-------------------< start here >-------------------------// 

const int N = 1e4 + 11;
bool isprime[N];
vector<int> primes;

void sieve(){
  fill(isprime + 2, isprime + N, true);
  
  for (int i = 2; i < N; i++){
	  if (isprime[i]){
		primes.push_back(i);
		for (int j = 2; i * j < N; j++){
		   isprime[i * j] = false;	
	    }  
	  }  
	}	
}

void solve(){
  sieve();
  int n;
  while (cin >> n){
	  vector<int> v1, v2;
	  int ret = 0;
	  for (int i = 1; i <= n; i++) v1.push_back(i);
	  for (int i = n; i >= 1; i--) v2.push_back(i);
      
	  for (int i = 1; i <= n; i++){
		 ret += isprime[i] && isprime[n - i + 1]; 
	  }
	 cout << ret << endl;  
	}	
}

//-----------------------------
//comment from here for TOPCODER 
int32_t main(){
   IOS;
   solve();
   //find();
   #ifdef LOCAL_DEFINE
   cerr << "time elapsed " << (double)clock()/CLOCKS_PER_SEC << endl;
   #endif
}
accuracy: 1
time_ms: 20
memory_kb: 3280
final_rank: 4

code_snippet: #include<iostream>
#include<cmath>
using namespace std;

bool judgePrime( int a )
{
    for( int i = 2; i <= sqrt(a); i++ )
    {
        if( a % i == 0 )
            return false;
    }
    return true;
}

int main()
{
    int n, a[10000], cnt;
    
    while( cin >> n )
    {
        for( int i = 0; i < n; i++ )
            a[i] = i + 1;
        
        cnt = 0;

        for( int i = 1; i < n - 1; i++ )
            if( judgePrime( a[i] ) && judgePrime( n - i ) )
                cnt++;
        
        cout << cnt << endl;
    }
    return 0;
}
accuracy: 1
time_ms: 120
memory_kb: 3140
final_rank: 14

code_snippet: #include "bits/stdc++.h"

using namespace std;
typedef set<int> sb;

sb criba(sb);
int main()
{
    int m,num,contador=0,caso;
    sb normal;
    sb arreglado;
    while(cin>>m)
    {
        contador = 0;
        for(int i = 0; i<m; i++)
        {
            normal.insert(i);
        }


        arreglado = criba(normal);
        set<int>::iterator it;
        set<int>::iterator am;

        for(it = arreglado.begin(); it!=arreglado.end(); it++)
        {
            num = m+1-*it;
            bool condicion = arreglado.find(num) != arreglado.end();
            if(condicion)
            {
                contador++;
            }
        }
        cout<<contador<<endl;
        normal.clear();
    }
    return 0;
}

sb criba(sb normal)
{
    int a = normal.size();
    normal.erase(0);
    normal.erase(1);

    for(int i = 2; i<a ; i++)
    {
        for(int j=i*i; j<=a; j = j+i)
        {
            normal.erase(j);
        }
    }

    return normal;
}
accuracy: 1
time_ms: 760
memory_kb: 4108
final_rank: 20

code_snippet: #include <iostream>
using namespace std;

bool isPrime(int n) {
    if (n == 0 || n == 1) return false;
    if (n == 2 || n == 3) return true;
    if (n % 2 == 0) return false;
    for (int i = 3; i * i <= n; i += 2) {
        if (n % i == 0) return false;
    }
    return true;
}

int main() {
    int n;
    while (cin >> n) {
        int count = 0;
        for (int i = 1; i <= n; i++) {
            if (isPrime(i) && isPrime(n + 1 - i)) {
                count++;
            }
        }
        cout << count << endl;
    }
    return 0;
}
accuracy: 1
time_ms: 50
memory_kb: 3016
final_rank: 6

code_snippet: #include<iostream>
#include<cmath>
using namespace std;
bool p(int n) {
    if (n == 2)return true;
    if (n % 2 == 0)return false;
    for (int i = 3; i <= sqrt(n); i += 2) if (n%i == 0)return false;
    return true;
}
int main(){
    int n; while (cin >> n){
        if (n < 3)cout << "0\n";
        else {
            int sum = 0;
            for (int i = 2; i < n; i++)
                if (p(i) && p(n - i + 1))sum++;
            cout << sum << endl;
        }
    }
}
accuracy: 1
time_ms: 60
memory_kb: 2980
final_rank: 8

code_snippet: #include<bits/stdc++.h>
using namespace std;

int n;

int isPrime(int a){
	if(a <= 1) return 0;
	if(a == 2) return 1;
	for(int i = 2; i * i <= a; i++){
		if(a % i == 0) return 0;
	}
	return 1;
}

int main(){
	while(cin >> n){
		int cnt = 0;
		for(int i = 1; i <= n; i++){
			if(isPrime(i) && isPrime(n - i + 1)) cnt++;
		}
		cout << cnt << endl;
	}
	return 0;
}
accuracy: 1
time_ms: 90
memory_kb: 2996
final_rank: 11

code_snippet: #include<iostream>
 #include<stdio.h>
 #include<string>
 #include<math.h>
 #include<iomanip>
 #include<algorithm>
 #include<string.h>
 #include<cctype>
 #include<map>
 #include<set>
 #include<vector>
 #include<sstream>
 #include<stack>
 #include<queue>
 
 using namespace std;
 
 bool arr[10000+5];
 
 bool is_prime(int x)
 {
   if(x==1) return false;
   else if(x==2) return true;
   else 
   {
     for(int i=2;i<=sqrt(x);i++)
     {
       if(x%i==0) return false;        
     }  
     return true;   
   }    
 }
 
 void init()
 {
   for(int i=1;i<=10000;i++)
   {
     if(is_prime(i)) arr[i]=true;
     else arr[i]=false;        
   }     
 }
 
 int main()
 {
   int N;
   while(cin>>N)
   {
     init();
     int count=0;
     for(int i=1;i<=(N/2);i++)
     {
       if(arr[i]&&arr[N-i+1])
       {
         //cout<<i<<" "<<N-i+1<<endl;
         count++;
       }           
     }
     if(N%2==0) cout<<(2*count)<<endl;
     else 
     {
       if(arr[N/2+1]) count=2*count+1;
       else count*=2;
       cout<<count<<endl;     
     }
   }
   //while(1);
   return 0;
 }
accuracy: 1
time_ms: 500
memory_kb: 3080
final_rank: 17

code_snippet: #include <iostream>
#include<math.h>

using namespace std;

int IsPrime(int a,int b)
{
    int i,p=0,q=0;
    if(a==1||b==1)
    {
        return 0;
    }
    for(i=2;i<=sqrt(a);i++)
    {

        if(a%i==0)
            {
                p=1;
                break;
            }
    }

    for(i=2;i<=sqrt(b);i++)
    {

        if(b%i==0)
            {
                q=1;
                break;
            }

    }
    if(p!=1&&q!=1)
        return 1;
    else
        return 0;

}
int main()
{
    int a,b,i,c=0;
    while( cin>>a)
    {
        c=0;

    for(i=0;i<a;i++)
    {
        if((b=IsPrime(i+1,a-i))==1)
            c++;

    }
    cout<<c<<endl;

}
}
accuracy: 1
time_ms: 190
memory_kb: 2992
final_rank: 15

code_snippet: #include<bits/stdc++.h>
  using namespace std;
  #define ll long long
  int main()
  {
 
       ll n,f,i,j;
          while(cin>>n)
          {
              f=0;
 
          vector<bool>v(n+1);
 
          for(i=0;i<=n;i++)
                  v[i]=1;
 
          v[0]=0;
          v[1]=0;
 
          for(i=2;i<=n;i++)
          {
                  if(v[i])
                  {
                          for(j=2*i;j<=n;j+=i)
                                  v[j]=0;
                  }
          }
 
 
 
          v.erase(v.begin());
          vector<bool>a(n);
          copy(v.rbegin(),v.rend(),a.begin());
 
          for(i=0;i<=n;i++)
          {
              if(a[i]&&v[i])
                 f++;
          }
          cout<<f<<endl;
 
          }
 
          return 0;
  }
accuracy: 1
time_ms: 30
memory_kb: 3060
final_rank: 5

code_snippet: #include<bits/stdc++.h>
using namespace std;

bool isprime(int a){
	for(int i=2;i*i<=a;i++){
		if(a%i==0)return false;
		}
		return a!=1;
	}

int main(){
	int n;
	while(cin>>n){
		int ans=0;
		for(int i=1;i<=n;i++){
			int b=n+1-i;
			if(isprime(b)&&isprime(i))ans++;
			}
			cout<<ans<<endl;
		}
		return 0;
	}
accuracy: 1
time_ms: 80
memory_kb: 3060
final_rank: 9

code_snippet: #include<iostream>
#include<string>
#include<cstdio>
#include<algorithm>
#include<stack>
#include<queue>
#include<vector>
#include<cmath>
#include<utility>
#include<set>
#include<complex>
#include<map>
#define vi vector<int>
#define vvi vector<vector<int> >
#define ll long long int
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vb vector<bool>
#define vc vector<char>
#define vs vector<string>
#define ld long double
#define INF 1e9
#define EPS 0.0000000001
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define CC puts("-------ok--------");
#define all(in) in.begin(), in.end()
using namespace std;
typedef pair<int, int> pii;
#define MAX 9999999
int main(){
    vector<bool>Primecheck(MAX+1,true);
    vector<int>Primenumber(MAX+1,0); //Primearray
    int Primecounter =0;                  //Primearray counter;
    for(int i = 2; i<MAX+1;i++){
        if(Primecheck[i]){
            for(int j = 2;i*j<MAX;j++)
                Primecheck[i*j] = false;//?´???°??????Primearray???????´??????????????????°?????¨???false???
            Primenumber[Primecounter] = i;
            Primecounter++;
        }
    }
    Primecheck[1]=false;
    int n;
    while(cin>>n){
        if(n==1){cout<<0<<endl; continue;}
        int ans=0;
        for(int i=1;i<=n;i++)
            if(Primecheck[i]&&Primecheck[n-i+1])ans++;
        cout<<ans<<endl;
    }
}
accuracy: 1
time_ms: 60
memory_kb: 42992
final_rank: 19

code_snippet: #include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <algorithm>
#include <sstream>
#include <cmath>
#include <set>
#include <iomanip>
#include <deque>
#include <stdio.h>
using namespace std;

#define REP(i,n) for(int (i)=0;(i)<(int)(n);(i)++)
#define RREP(i,n) for(int (i)=(int)(n)-1;i>=0;i--)
#define iREP(i,Itr) for(auto (i)=(Itr).begin();(i)!=(Itr).end();(i)++)
#define REMOVE(Itr,n) (Itr).erase(remove((Itr).begin(),(Itr).end(),n),(Itr).end())
#define PB_VEC(Itr1,Itr2) (Itr1).insert((Itr1).end(),(Itr2).begin(),(Itr2).end())
#define UNIQUE(Itr) sort((Itr).begin(),(Itr).end()); (Itr).erase(unique((Itr).begin(),(Itr).end()),(Itr).end())
#define LBOUND(Itr,val) lower_bound((Itr).begin(),(Itr).end(),(val))
#define UBOUND(Itr,val) upper_bound((Itr).begin(),(Itr).end(),(val))
typedef long long ll;

bool isPrime(int n){
    if(n==1)return false;
    if(n==2)return true;
    for(int i=2;i<sqrt(n)+1;i++){
        if((n%i)==0)return false;
    }
    return true;
}

int main(){
    
    int n;
    while(cin>>n){
        int cnt=0;
        REP(i,n){
            if(isPrime(i+1)&&isPrime(n-i))cnt++;
        }
        cout<<cnt<<endl;
    }
    
    return 0;
}
accuracy: 1
time_ms: 110
memory_kb: 3060
final_rank: 13

code_snippet: #include "bits/stdc++.h"
#include<unordered_map>
#include<unordered_set>
#pragma warning(disable:4996)
using namespace std;
using ld = long double;
template<class T>
using Table = vector<vector<T>>;
const ld eps = 1e-9;

//// < "D:\D_Download\Visual Studio 2015\Projects\programing_contest_c++\Debug\a.txt" > "D:\D_Download\Visual Studio 2015\Projects\programing_contest_c++\Debug\b.txt"
  
bool isso(long long int a) {
	if (a == 1 || a == 0)return false;
	for (long long int i = 2; i*i <= a; ++i) {
		if ((a%i)) {
		}
		else {
			return false;
		}
	}
	return true;
}
int main() {
	int N;
	while (cin >> N) {
		int ans = 0;
		for (int i = 1; i <= N; ++i) {
			int j = N + 1 - i;
			if (isso(i) && isso(j))ans++;
		}
		cout << ans << endl;
	}
	return 0;
}
accuracy: 1
time_ms: 240
memory_kb: 3052
final_rank: 16

code_snippet: #include <bits/stdc++.h>

#define REP(i,n) for(int i=0;i<(int)n;++i)

using namespace std;

int main() {
  int n;
  while(scanf("%d",&n) != EOF) {
    vector<bool> isp(n+1, true);
    isp[0] = isp[1] = false;
    for (int i = 2; i*i <= n; ++i)
      if (isp[i])
        for (int j = i*i; j <= n; j += i)
          isp[j] = false;
    int cnt = 0;
    for (int i = 1; i <= n; ++i)
      if (isp[i] && isp[n-i+1])
        ++cnt;
    cout << cnt << endl;
  }
  return 0;
}
accuracy: 1
time_ms: 10
memory_kb: 3144
final_rank: 3

code_snippet: #include<bits/stdc++.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) range(i,0,b)
#define pb(a) push_back(a)
#define all(a) (a).begin(), (a).end()
#define debug(x) cout << "debug " << x << endl;
using namespace std;

#define N 10005

int main(){
    int n;
    while(cin >> n){
        bool prime[N], pairPrime[N];

        n++;
        rep(i,n) prime[i] = 1;
        prime[0] = prime[1] = 0;

        int primeSum[N] = {0};
        rep(i,n){
            if(prime[i]){
                for(int j = i + i; j <= n; j+=i) prime[j] = 0;
            }
        }

        range(i,1,n) pairPrime[i] = (prime[i] && prime[n - i]);

        int count = 0;
        rep(i,n){
            count+=static_cast<int>(pairPrime[i]);
        }
        cout << count << endl;
    }
}
accuracy: 1
time_ms: 20
memory_kb: 1180
final_rank: 2

code_snippet: #include<iostream>
using namespace std;int prime[30];int main(){int count=1;prime[0]=2;for(int i=3;i<100;i+=2){bool t=true;for(int j=1;j<count;j++){if(i%prime[j]==0)t=false;}if(t==true){prime[count]=i;count++;}}int n;while(cin>>n){n++;int ans=0;for(int cut=2;cut<n-1;cut++){bool t=true,f=true;for(int i=0;i<count;i++){if(cut%prime[i]==0&&cut!=prime[i])t=false;}for(int i=0;i<count;i++){if((n-cut)%prime[i]==0&&n-cut!=prime[i])f=false;}if(t==true&&f==true)ans++;}cout<<ans<<endl;}return 0;}
accuracy: 1
time_ms: 620
memory_kb: 1160
final_rank: 18

code_snippet: #include <iostream>
#include <cmath>
using namespace std;

void sieve(bool *primes, int n)
{
  int m = ceil(sqrt(n));
  int k = 2;

  for (int i=0;i<=n;i++) primes[i]=true;
  primes[0] = primes[1] = false;

  for (int i=2;i<=m;i++)
  {
    if (primes[i])
    {
      for (int k=2*i; k<=n; k+=i)
        primes[k] = false;
    }
  }
}

int main()
{
  bool primes[10001];
  int ns[10000];
  int num = 0;
  int maxn = 0;
  int n;

  while (cin >> n)
  {
    ns[num] = n;
    maxn = max(maxn, n);
    num++;
  }

  sieve(primes, maxn);

  for (int i=0;i<num;i++)
  {
    int p = 1;
    int q = ns[i];
    int ans = 0;
    for (int j=0;j<ns[i];j++)
    {
      if (primes[p] && primes[q]) ans++;
      p++;
      q--;
    }
    cout << ans << endl;
  }

  return 0;
}
accuracy: 1
time_ms: 10
memory_kb: 1180
final_rank: 1