Problem p03168 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPR(i, n) for (int i = n; i >= 0; i--)
#define FOR(i, m, n) for (int i = m; i < n; i++)
#define fi first
#define se second
#define mp make_pair
#define itrfor(itr, A) for (auto itr = A.begin(); itr != A.end(); itr++)
template <class T>
using reversed_priority_queue = priority_queue<T, vector<T>, greater<T>>;
typedef long long llong;
char moji[26] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i',
                 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r',
                 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
char moji2[26] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I',
                  'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
                  'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
char moji3[10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
#define Sort(a) sort(a.begin(), a.end());
#define Reverse(a) reverse(a.begin(), a.end());
#define print(a) cout << a << endl;
#define MOD llong(1e9 + 7)
#define MAX int(2 * 1e5 + 5)
#define debug(x) cout << #x << " = " << (x) << endl;
#define pi acos(-1.0)
#define int llong
#define INF llong(1e17)
template <class T> bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
void myprint(int *A, int A_num) {
  REP(i, A_num) cout << A[i] << " ";
  cout << endl;
}

const int n_max = 305;

signed main() {
  int n;
  cin >> n;
  double p[n];
  REP(i, n) cin >> p[i];
  double dp[n_max][n_max];

  REP(i, n + 1) REP(j, i + 1) dp[i][j] = 0.0;
  dp[0][0] = 1.0;
  REP(i, n) {
    REP(j, i + 2) {
      if (j != 0 and j != i + 1) {
        dp[i + 1][j] = p[i] * dp[i][j - 1] + (1 - p[i]) * dp[i][j];
      } else if (j == 0) {
        dp[i + 1][j] = (1 - p[i]) * dp[i][j];
      } else
        dp[i + 1][j] = p[i] * dp[i][j - 1];
    }
  }

  double ans = 0.0;
  FOR(i, n / 2 + 1, n + 1) { ans += dp[n][i]; }

  cout << fixed << setprecision(12) << ans << endl;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPR(i, n) for (int i = n; i >= 0; i--)
#define FOR(i, m, n) for (int i = m; i < n; i++)
#define fi first
#define se second
#define mp make_pair
#define itrfor(itr, A) for (auto itr = A.begin(); itr != A.end(); itr++)
template <class T>
using reversed_priority_queue = priority_queue<T, vector<T>, greater<T>>;
typedef long long llong;
char moji[26] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i',
                 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r',
                 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
char moji2[26] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I',
                  'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
                  'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
char moji3[10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
#define Sort(a) sort(a.begin(), a.end());
#define Reverse(a) reverse(a.begin(), a.end());
#define print(a) cout << a << endl;
#define MOD llong(1e9 + 7)
#define MAX int(2 * 1e5 + 5)
#define debug(x) cout << #x << " = " << (x) << endl;
#define pi acos(-1.0)
#define int llong
#define INF llong(1e17)
template <class T> bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
void myprint(int *A, int A_num) {
  REP(i, A_num) cout << A[i] << " ";
  cout << endl;
}

const int n_max = 3005;

signed main() {
  int n;
  cin >> n;
  double p[n];
  REP(i, n) cin >> p[i];
  double dp[n_max][n_max];

  REP(i, n + 1) REP(j, i + 1) dp[i][j] = 0.0;
  dp[0][0] = 1.0;
  REP(i, n) {
    REP(j, i + 2) {
      if (j != 0 and j != i + 1) {
        dp[i + 1][j] = p[i] * dp[i][j - 1] + (1 - p[i]) * dp[i][j];
      } else if (j == 0) {
        dp[i + 1][j] = (1 - p[i]) * dp[i][j];
      } else
        dp[i + 1][j] = p[i] * dp[i][j - 1];
    }
  }

  double ans = 0.0;
  FOR(i, n / 2 + 1, n + 1) { ans += dp[n][i]; }

  cout << fixed << setprecision(12) << ans << endl;
}