Problem p02716 (C++) — buggy submission, verdict: Runtime Error

#ifdef LOCAL
#define _GLIBCXX_DEBUG
#define __clock__
#else
#pragma GCC optimize("Ofast")
#endif
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;

// tourist set
template <typename A, typename B> string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string &s) { return '"' + s + '"'; }

string to_string(const char *s) { return to_string((string)s); }

string to_string(bool b) { return (b ? "true" : "false"); }

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N> string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A> string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B> string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << '\\n'; }

template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

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

#define FOR(i, a, b) for (ll i = (a); i < (b); ++i)
#define rep(i, b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout << (s) << '\\n'
#define p2(s, t) cout << (s) << " " << (t) << '\\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\\n'
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())
#define MP make_pair
#define p_yes() p("Yes")
#define p_no() p("No")

ll SUM(VI &V) { return accumulate(ALL(V), 0LL); }

ll MIN(VI &V) { return *min_element(ALL(V)); }
ll MAX(VI &V) { return *max_element(ALL(V)); }

void print_vector(VI &V) {
  ll n = V.size();
  rep(i, n) {
    if (i)
      cout << ' ';
    cout << V[i];
  }
  cout << endl;
}

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
  ll g = gcd(a, b);
  return a / g * b;
}

// long double
using ld = long double;
#define EPS (1e-14)
#define equals(a, b) (fabs((a) - (b)) < EPS)

void no() {
  p_no();
  exit(0);
}
void yes() {
  p_yes();
  exit(0);
}

const ll mod = 1e9 + 7;
const ll inf = 1e18;
const double PI = acos(-1);

ll dp[200010][2][3];
void reset() { rep(i, 200010) rep(j, 2) rep(k, 3) dp[i][j][k] = -inf; }

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  // input
  ll N;
  cin >> N;

  VI A(N + 10);
  rep(i, N) cin >> A[i];

  if (N == 2) {
    ll ans = max(A[0], A[1]);
    p(ans);
    return 0;
  }

  reset();
  dp[0][0][0] = 0;
  dp[0][1][0] = A[0];

  dp[2][1][1] = A[2]; // いきなり大ジャンプ

  rep(i, N) {
    rep(j, 2) {
      rep(k, 3) {
        if (j == 0) {
          if (k != 2) {
            // 大ジャンプ可能
            // 1歩先を選ばない(大ジャンプ)
            chmax(dp[i + 1][0][k + 1], dp[i][j][k] + 0);
            // 2歩先を選ぶ(大ジャンプ)
            chmax(dp[i + 2][1][k + 1], dp[i][j][k] + A[i + 2]);
          }
          // 1歩先を選ぶ
          chmax(dp[i + 1][1][k], dp[i][j][k] + A[i + 1]);
        } else {
          // j==1 (選んでる)
          if (k != 2) {
            // 大ジャンプ可能
            // 3歩先を選ぶ(大ジャンプ)
            chmax(dp[i + 3][1][k + 1], dp[i][j][k] + A[i + 3]);
          }
          // 1歩先を選ばない
          chmax(dp[i + 1][0][k], dp[i][j][k] + 0);
          // 2歩先を選ぶ
          chmax(dp[i + 2][1][k], dp[i][j][k] + A[i + 2]);
        }
      }
    }
  }
  rep(i, 4) {
    debug(i);
    debug(dp[i][0][0]);
    debug(dp[i][0][1]);
    debug(dp[i][1][0]);
    debug(dp[i][1][1]);
  }

  ll ans = -1;
  if (N % 2 == 0) {
    VI A;
    A.push_back(dp[N - 1][1][0]);
    A.push_back(dp[N - 1][1][1]);
    A.push_back(dp[N - 1][0][0]);

    ans = MAX(A);
  } else {
    VI A;
    A.push_back(dp[N - 1][1][1]);
    A.push_back(dp[N - 1][1][2]);
    A.push_back(dp[N - 1][0][1]);
    A.push_back(dp[N - 1][0][0]);
    debug(A);
    ans = MAX(A);
    // ll a = dp[N-3][1][0];
    // ll b = dp[N-2][1][0];
    // ll c = dp[N-1][1][1];
    // ans = max({a,b,c});
  }
  p(ans);

  return 0;
}

Error: 0

Fixed submission:

#ifdef LOCAL
#define _GLIBCXX_DEBUG
#define __clock__
#else
#pragma GCC optimize("Ofast")
#endif
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;

// tourist set
template <typename A, typename B> string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string &s) { return '"' + s + '"'; }

string to_string(const char *s) { return to_string((string)s); }

string to_string(bool b) { return (b ? "true" : "false"); }

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N> string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A> string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B> string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << '\\n'; }

template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

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

#define FOR(i, a, b) for (ll i = (a); i < (b); ++i)
#define rep(i, b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout << (s) << '\\n'
#define p2(s, t) cout << (s) << " " << (t) << '\\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\\n'
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())
#define MP make_pair
#define p_yes() p("Yes")
#define p_no() p("No")

ll SUM(VI &V) { return accumulate(ALL(V), 0LL); }

ll MIN(VI &V) { return *min_element(ALL(V)); }
ll MAX(VI &V) { return *max_element(ALL(V)); }

void print_vector(VI &V) {
  ll n = V.size();
  rep(i, n) {
    if (i)
      cout << ' ';
    cout << V[i];
  }
  cout << endl;
}

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
  ll g = gcd(a, b);
  return a / g * b;
}

// long double
using ld = long double;
#define EPS (1e-14)
#define equals(a, b) (fabs((a) - (b)) < EPS)

void no() {
  p_no();
  exit(0);
}
void yes() {
  p_yes();
  exit(0);
}

const ll mod = 1e9 + 7;
const ll inf = 1e18;
const double PI = acos(-1);

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  // input
  ll N;
  cin >> N;

  VI A(N);
  rep(i, N) cin >> A[i];

  if (N % 2 == 0) {
    ll a = 0;
    ll b = 0;
    rep(i, N / 2) {
      a += A[2 * i];
      b += A[2 * i + 1];
    }
    ll ma = max(a, b);
    p(ma);
    return 0;
  }

  assert(1 == 0);

  return 0;
}