Problem p03171 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define reps(i, s, n) for (int i = (s); i < (n); i++)
#define all(v) v.begin(), v.end()
#define outve(v)                                                               \
  for (auto i : v)                                                             \
    cout << i << " ";                                                          \
  cout << endl
#define outmat(v)                                                              \
  for (auto i : v) {                                                           \
    for (auto j : i)                                                           \
      cout << j << " ";                                                        \
    cout << endl;                                                              \
  }
#define in(n, v)                                                               \
  for (int i = 0; i < (n); i++) {                                              \
    cin >> v[i];                                                               \
  }
#define out(n) cout << (n) << endl
#define fi first
#define se second
#define pb push_back
#define mod 1000000007
#define infi 1900000000
#define infl 1100000000000000000
#define cyes cout << "Yes" << endl
#define cno cout << "No" << endl
#define csp << " " <<
#define outset(n) cout << fixed << setprecision(n);
using namespace std;
using ll = long long;
using ld = long double;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vs = vector<string>;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vvp = vector<vector<pair<int, int>>>;
template <typename T> using ve = vector<T>;
template <typename T> using pq2 = priority_queue<T>;
template <typename T> using pq1 = priority_queue<T, vector<T>, greater<T>>;
template <typename T> bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T> bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}

int main() {

  int N;
  cin >> N;
  vl a(N);
  in(N, a);

  vvl dp(3100, vl(3100, 0));

  reps(aa, 1, N + 1) {
    rep(i, N + 1) {
      int j = aa + i;
      if ((N - (j - i)) % 2 == 0) {
        dp[i][j] = max(dp[i + 1][j] + a[i], dp[i][j - 1] + a[j - 1]);
      } else {
        dp[i][j] = min(dp[i + 1][j] - a[i], dp[i][j - 1] - a[j - 1]);
      }
    }
  }

  // outmat(dp);
  cout << dp[0][N] << endl;

  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define reps(i, s, n) for (int i = (s); i < (n); i++)
#define all(v) v.begin(), v.end()
#define outve(v)                                                               \
  for (auto i : v)                                                             \
    cout << i << " ";                                                          \
  cout << endl
#define outmat(v)                                                              \
  for (auto i : v) {                                                           \
    for (auto j : i)                                                           \
      cout << j << " ";                                                        \
    cout << endl;                                                              \
  }
#define in(n, v)                                                               \
  for (int i = 0; i < (n); i++) {                                              \
    cin >> v[i];                                                               \
  }
#define out(n) cout << (n) << endl
#define fi first
#define se second
#define pb push_back
#define mod 1000000007
#define infi 1900000000
#define infl 1100000000000000000
#define cyes cout << "Yes" << endl
#define cno cout << "No" << endl
#define csp << " " <<
#define outset(n) cout << fixed << setprecision(n);
using namespace std;
using ll = long long;
using ld = long double;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vs = vector<string>;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vvp = vector<vector<pair<int, int>>>;
template <typename T> using ve = vector<T>;
template <typename T> using pq2 = priority_queue<T>;
template <typename T> using pq1 = priority_queue<T, vector<T>, greater<T>>;
template <typename T> bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T> bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}

int main() {

  int N;
  cin >> N;
  vl a(N);
  in(N, a);

  vvl dp(7100, vl(7100, 0));

  reps(aa, 1, N + 1) {
    rep(i, N + 1) {
      int j = aa + i;
      if ((N - (j - i)) % 2 == 0) {
        dp[i][j] = max(dp[i + 1][j] + a[i], dp[i][j - 1] + a[j - 1]);
      } else {
        dp[i][j] = min(dp[i + 1][j] - a[i], dp[i][j - 1] - a[j - 1]);
      }
    }
  }

  // outmat(dp);
  cout << dp[0][N] << endl;

  return 0;
}