Problem p02586 (C++)

Buggy submission (status: Time Limit Exceeded):
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
constexpr long long INF = 1LL << 60;
constexpr long long MOD = 1000000007;
double PI = acos(-1.0);
#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rep1(i, n) for (ll i = 1; i <= (n); ++i)
#define rrep(i, n) for (ll i = (n - 1); i >= 0; --i)
#define perm(c)                                                                \
  sort(ALL(c));                                                                \
  for (bool c##p = 1; c##p; c##p = next_permutation(ALL(c)))
#define ALL(obj) (obj).begin(), (obj).end()
#define RALL(obj) (obj).rbegin(), (obj).rend()
#define pb push_back
#define to_s to_string
#define len(v) (ll) v.size()
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define print(x) cout << (x) << '\n'
#define drop(x) cout << (x) << '\n', exit(0)
#define debug(x) cout << #x << ": " << (x) << '\n'
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> tpl;
typedef vector<ll> vec;
typedef vector<vector<ll>> vec2;
typedef vector<vector<vector<ll>>> vec3;
template <class S, class T> inline bool chmax(S &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class S, class T> inline bool chmin(S &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
inline ll msb(ll v) { return 1 << (31 - __builtin_clzll(v)); }
inline ll devc(ll x, ll y) { return (x + y - 1) / y; }
inline ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
inline ll lcm(ll a, ll b) { return a * (b / gcd(a, b)); }

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t);
  return os;
}

template <typename T1, typename T2, typename T3>
istream &operator>>(istream &is, tuple<T1, T2, T3> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t);
  return is;
}

template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); ++i) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v)
    is >> in;
  return is;
}

template <typename T> ostream &operator<<(ostream &os, const set<T> &st) {
  int ct = 0;
  for (auto &s : st)
    cout << s << (++ct != st.size() ? " " : "");
  return os;
}

template <typename T>
constexpr set<T> &operator|=(set<T> &st1, const set<T> &st2) {
  for (auto &s : st2)
    st1.insert(s);
  return st1;
}

template <typename T>
constexpr set<T> &operator-=(set<T> &st1, const set<T> &st2) {
  for (auto &s : st2)
    if (st1.count(s))
      st1.erase(s);
  return st1;
}

template <typename T>
constexpr set<T> &operator&=(set<T> &st1, const set<T> &st2) {
  auto itr = st1.begin();
  while (itr != st1.end()) {
    if (!st2.count(*itr))
      itr = st1.erase(itr);
    else
      ++itr;
  }
  return st1;
}

template <typename T>
constexpr set<T> operator|(const set<T> &st1, const set<T> &st2) {
  set<T> res = st1;
  res |= st2;
  return res;
}

template <typename T>
constexpr set<T> operator-(const set<T> &st1, const set<T> &st2) {
  set<T> res = st1;
  res -= st2;
  return res;
}

template <typename T>
constexpr set<T> operator&(const set<T> &st1, const set<T> &st2) {
  set<T> res = st1;
  res &= st2;
  return res;
}

/*---------------------------------    Tools
 * ------------------------------------------*/
template <typename T> vector<T> cumsum(const vector<T> &X) {
  vector<T> res(X.size() + 1, 0);
  for (int i = 0; i < X.size(); ++i)
    res[i + 1] += res[i] + X[i];
  return res;
}

template <typename S, typename T, typename F>
pair<T, T> bisearch(S left, T right, F f) {
  while (abs(right - left) > 1) {
    T mid = (right + left) / 2;
    if (f(mid))
      right = mid;
    else
      left = mid;
  }
  return {left, right};
}

template <typename S, typename T, typename F>
double trisearch(S left, T right, F f, int maxLoop = 90) {
  double low = left, high = right;
  while (maxLoop--) {
    double mid_left = high / 3 + low * 2 / 3;
    double mid_right = high * 2 / 3 + low / 3;
    if (f(mid_left) >= f(mid_right))
      low = mid_left;
    else
      high = mid_right;
  }
  return (low + high) * 0.5;
}

template <typename F> ll ternarySearch(ll L, ll R, F f) { //[L, R)
  ll lo = L - 1, hi = R - 1;
  while (lo + 1 != hi) {
    ll mi = (lo + hi) / 2;
    if (f(mi) <= f(mi + 1))
      hi = mi;
    else
      lo = mi;
  }
  return hi;
}

/*---------------------------------    Graph
 * ------------------------------------------*/
struct Graph {
  struct Edge {
    ll from, to, weight;
    Edge() : from(0), to(0), weight(0) {}
    Edge(ll f, ll t, ll w) : from(f), to(t), weight(w) {}
  };
  using Edges = vector<Edge>;

  vector<Edges> G;

  Graph() : G(){};

  Graph(int N) : G(N) {}

  Edges operator[](int k) const { return G[k]; }

  ll size() const { return G.size(); }

  void resize(int N) { G.resize(N); }

  void add_edge(int a, int b, ll w = 1) {
    G[a].emplace_back(a, b, w);
    G[b].emplace_back(b, a, w);
  }

  void add_arrow(int a, int b, ll w = 1) { G[a].emplace_back(a, b, w); }

  // Topological_sort
  //!!return empty, if not DAG
  vector<ll> topological_sort() const;

  // Dijkstra and related
  vector<ll> dijkstra(ll s, bool restore = false) const;

  vector<ll> shortest_path(ll start, ll goal) const;

  // Bellman-Ford
  //!!return empty, if negative loop exists
  vector<ll> bellman_ford(ll s) const;

  // Warshall-Floyd
  vector<vector<ll>> Warshall_Floyd() const;

  // Kruskal
  //!!Required UnionFind
  Graph Kruskal() const;
};

vector<ll> Graph::dijkstra(ll s, bool restore) const {
  vector<ll> dist(G.size(), INF);
  priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> que;
  dist[s] = 0;
  que.emplace(dist[s], s);

  vector<ll> prev(G.size(), -1);

  while (!que.empty()) {
    ll cost, idx;
    tie(cost, idx) = que.top();
    que.pop();
    if (dist[idx] < cost)
      continue;
    for (auto &e : G[idx]) {
      auto next_cost = cost + e.weight;
      if (dist[e.to] <= next_cost)
        continue;
      dist[e.to] = next_cost;

      if (restore)
        prev[e.to] = e.from;
      que.emplace(dist[e.to], e.to);
    }
  }
  if (restore)
    return prev;
  return dist;
}

vector<ll> Graph::shortest_path(ll start, ll goal) const {
  vector<ll> prev = dijkstra(start, true);
  vector<ll> path;
  for (int cur = goal; cur != -1; cur = prev[cur])
    path.push_back(cur);
  reverse(path.begin(), path.end());
  if (path.front() != start)
    return {};
  return path;
}

vector<ll> Graph::bellman_ford(ll s) const {
  vector<ll> dist(G.size(), INF);
  dist[s] = 0;
  for (ll i = 0; i < G.size(); ++i) {
    for (ll j = 0; j < G.size(); ++j) {
      for (auto &e : G[j]) {
        if (dist[e.from] == INF)
          continue;
        bool res = chmin(dist[e.to], dist[e.from] + e.weight);
        if (i == G.size() - 1 and res)
          return {};
      }
    }
  }
  return dist;
}

vector<vector<ll>> Graph::Warshall_Floyd() const {
  int N = G.size();
  vector<vector<ll>> d(N, vector<ll>(N));

  rep(i, N) rep(j, N) {
    if (i == j)
      d[i][j] = 0;
    else
      d[i][j] = INF;
  }

  rep(i, N) for (auto &e : G[i]) d[i][e.to] = e.weight;
  rep(k, N) rep(i, N) rep(j, N) {
    if (d[i][k] == INF or d[k][j] == INF)
      continue;
    d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
  }
  return d;
}

vector<ll> Graph::topological_sort() const {
  vector<ll> ans;
  int N = G.size();
  vector<int> ind(N);
  rep(i, N) for (auto &e : G[i]) ind[e.to]++;
  queue<int> que;
  rep(i, N) if (!ind[i]) que.push(i);
  while (!que.empty()) {
    int now = que.front();
    ans.pb(now);
    que.pop();
    for (auto &e : G[now]) {
      ind[e.to]--;
      if (!ind[e.to])
        que.push(e.to);
    }
  }
  if (ans.size() != N)
    return {};
  return ans;
}

/*------------------------------- Main Code Here
 * -----------------------------------------*/

int main() {
  ll R, C, K;
  cin >> R >> C >> K;

  vec2 mx(R + 1, vec(C + 1));
  rep(i, K) {
    ll r, c, v;
    cin >> r >> c >> v;
    mx[r][c] = v;
  }

  vec2 res(R + 1, vec(C + 1, -1));

  auto f = [&](auto &self, ll x, ll y, vec tp) -> ll {
    if (x > R or y > C)
      return 0;
    // if(res[x][y] != -1) return res[x][y];

    sort(ALL(tp));
    if (mx[x][y] > tp[0])
      tp[0] = mx[x][y];
    ll sum = accumulate(ALL(tp), 0LL);
    return res[x][y] = max(self(self, x + 1, y, {0, 0, 0}) + sum,
                           self(self, x, y + 1, tp));
  };

  print(f(f, 0, 0, {0, 0, 0}));

  return 0;
}

Fixed submission:
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
constexpr long long INF = 1LL << 60;
constexpr long long MOD = 1000000007;
double PI = acos(-1.0);
#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rep1(i, n) for (ll i = 1; i <= (n); ++i)
#define rrep(i, n) for (ll i = (n - 1); i >= 0; --i)
#define perm(c)                                                                \
  sort(ALL(c));                                                                \
  for (bool c##p = 1; c##p; c##p = next_permutation(ALL(c)))
#define ALL(obj) (obj).begin(), (obj).end()
#define RALL(obj) (obj).rbegin(), (obj).rend()
#define pb push_back
#define to_s to_string
#define len(v) (ll) v.size()
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define print(x) cout << (x) << '\n'
#define drop(x) cout << (x) << '\n', exit(0)
#define debug(x) cout << #x << ": " << (x) << '\n'
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> tpl;
typedef vector<ll> vec;
typedef vector<vector<ll>> vec2;
typedef vector<vector<vector<ll>>> vec3;
template <class S, class T> inline bool chmax(S &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class S, class T> inline bool chmin(S &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
inline ll msb(ll v) { return 1 << (31 - __builtin_clzll(v)); }
inline ll devc(ll x, ll y) { return (x + y - 1) / y; }
inline ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
inline ll lcm(ll a, ll b) { return a * (b / gcd(a, b)); }

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t);
  return os;
}

template <typename T1, typename T2, typename T3>
istream &operator>>(istream &is, tuple<T1, T2, T3> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t);
  return is;
}

template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); ++i) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v)
    is >> in;
  return is;
}

template <typename T> ostream &operator<<(ostream &os, const set<T> &st) {
  int ct = 0;
  for (auto &s : st)
    cout << s << (++ct != st.size() ? " " : "");
  return os;
}

template <typename T>
constexpr set<T> &operator|=(set<T> &st1, const set<T> &st2) {
  for (auto &s : st2)
    st1.insert(s);
  return st1;
}

template <typename T>
constexpr set<T> &operator-=(set<T> &st1, const set<T> &st2) {
  for (auto &s : st2)
    if (st1.count(s))
      st1.erase(s);
  return st1;
}

template <typename T>
constexpr set<T> &operator&=(set<T> &st1, const set<T> &st2) {
  auto itr = st1.begin();
  while (itr != st1.end()) {
    if (!st2.count(*itr))
      itr = st1.erase(itr);
    else
      ++itr;
  }
  return st1;
}

template <typename T>
constexpr set<T> operator|(const set<T> &st1, const set<T> &st2) {
  set<T> res = st1;
  res |= st2;
  return res;
}

template <typename T>
constexpr set<T> operator-(const set<T> &st1, const set<T> &st2) {
  set<T> res = st1;
  res -= st2;
  return res;
}

template <typename T>
constexpr set<T> operator&(const set<T> &st1, const set<T> &st2) {
  set<T> res = st1;
  res &= st2;
  return res;
}

/*---------------------------------    Tools
 * ------------------------------------------*/
template <typename T> vector<T> cumsum(const vector<T> &X) {
  vector<T> res(X.size() + 1, 0);
  for (int i = 0; i < X.size(); ++i)
    res[i + 1] += res[i] + X[i];
  return res;
}

template <typename S, typename T, typename F>
pair<T, T> bisearch(S left, T right, F f) {
  while (abs(right - left) > 1) {
    T mid = (right + left) / 2;
    if (f(mid))
      right = mid;
    else
      left = mid;
  }
  return {left, right};
}

template <typename S, typename T, typename F>
double trisearch(S left, T right, F f, int maxLoop = 90) {
  double low = left, high = right;
  while (maxLoop--) {
    double mid_left = high / 3 + low * 2 / 3;
    double mid_right = high * 2 / 3 + low / 3;
    if (f(mid_left) >= f(mid_right))
      low = mid_left;
    else
      high = mid_right;
  }
  return (low + high) * 0.5;
}

template <typename F> ll ternarySearch(ll L, ll R, F f) { //[L, R)
  ll lo = L - 1, hi = R - 1;
  while (lo + 1 != hi) {
    ll mi = (lo + hi) / 2;
    if (f(mi) <= f(mi + 1))
      hi = mi;
    else
      lo = mi;
  }
  return hi;
}

/*---------------------------------    Graph
 * ------------------------------------------*/
struct Graph {
  struct Edge {
    ll from, to, weight;
    Edge() : from(0), to(0), weight(0) {}
    Edge(ll f, ll t, ll w) : from(f), to(t), weight(w) {}
  };
  using Edges = vector<Edge>;

  vector<Edges> G;

  Graph() : G(){};

  Graph(int N) : G(N) {}

  Edges operator[](int k) const { return G[k]; }

  ll size() const { return G.size(); }

  void resize(int N) { G.resize(N); }

  void add_edge(int a, int b, ll w = 1) {
    G[a].emplace_back(a, b, w);
    G[b].emplace_back(b, a, w);
  }

  void add_arrow(int a, int b, ll w = 1) { G[a].emplace_back(a, b, w); }

  // Topological_sort
  //!!return empty, if not DAG
  vector<ll> topological_sort() const;

  // Dijkstra and related
  vector<ll> dijkstra(ll s, bool restore = false) const;

  vector<ll> shortest_path(ll start, ll goal) const;

  // Bellman-Ford
  //!!return empty, if negative loop exists
  vector<ll> bellman_ford(ll s) const;

  // Warshall-Floyd
  vector<vector<ll>> Warshall_Floyd() const;

  // Kruskal
  //!!Required UnionFind
  Graph Kruskal() const;
};

vector<ll> Graph::dijkstra(ll s, bool restore) const {
  vector<ll> dist(G.size(), INF);
  priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> que;
  dist[s] = 0;
  que.emplace(dist[s], s);

  vector<ll> prev(G.size(), -1);

  while (!que.empty()) {
    ll cost, idx;
    tie(cost, idx) = que.top();
    que.pop();
    if (dist[idx] < cost)
      continue;
    for (auto &e : G[idx]) {
      auto next_cost = cost + e.weight;
      if (dist[e.to] <= next_cost)
        continue;
      dist[e.to] = next_cost;

      if (restore)
        prev[e.to] = e.from;
      que.emplace(dist[e.to], e.to);
    }
  }
  if (restore)
    return prev;
  return dist;
}

vector<ll> Graph::shortest_path(ll start, ll goal) const {
  vector<ll> prev = dijkstra(start, true);
  vector<ll> path;
  for (int cur = goal; cur != -1; cur = prev[cur])
    path.push_back(cur);
  reverse(path.begin(), path.end());
  if (path.front() != start)
    return {};
  return path;
}

vector<ll> Graph::bellman_ford(ll s) const {
  vector<ll> dist(G.size(), INF);
  dist[s] = 0;
  for (ll i = 0; i < G.size(); ++i) {
    for (ll j = 0; j < G.size(); ++j) {
      for (auto &e : G[j]) {
        if (dist[e.from] == INF)
          continue;
        bool res = chmin(dist[e.to], dist[e.from] + e.weight);
        if (i == G.size() - 1 and res)
          return {};
      }
    }
  }
  return dist;
}

vector<vector<ll>> Graph::Warshall_Floyd() const {
  int N = G.size();
  vector<vector<ll>> d(N, vector<ll>(N));

  rep(i, N) rep(j, N) {
    if (i == j)
      d[i][j] = 0;
    else
      d[i][j] = INF;
  }

  rep(i, N) for (auto &e : G[i]) d[i][e.to] = e.weight;
  rep(k, N) rep(i, N) rep(j, N) {
    if (d[i][k] == INF or d[k][j] == INF)
      continue;
    d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
  }
  return d;
}

vector<ll> Graph::topological_sort() const {
  vector<ll> ans;
  int N = G.size();
  vector<int> ind(N);
  rep(i, N) for (auto &e : G[i]) ind[e.to]++;
  queue<int> que;
  rep(i, N) if (!ind[i]) que.push(i);
  while (!que.empty()) {
    int now = que.front();
    ans.pb(now);
    que.pop();
    for (auto &e : G[now]) {
      ind[e.to]--;
      if (!ind[e.to])
        que.push(e.to);
    }
  }
  if (ans.size() != N)
    return {};
  return ans;
}

/*------------------------------- Main Code Here
 * -----------------------------------------*/

int main() {
  ll R, C, K;
  cin >> R >> C >> K;

  vec2 mx(R + 1, vec(C + 1));
  rep(i, K) {
    ll r, c, v;
    cin >> r >> c >> v;
    mx[r][c] = v;
  }

  vec3 res(4, vec2(R + 1, vec(C + 1, 0)));

  rep1(j, R) rep1(k, C) {
    // 変化なし
    rep(i, 4) chmax(res[0][j][k], res[i][j - 1][k]);
    rep(i, 4) chmax(res[i][j][k], res[i][j][k - 1]);

    // 取る場合
    rrep(i, 4) if (i) chmax(res[i][j][k], res[i - 1][j][k] + mx[j][k]);
  }

  // for(auto r : res[3]) print(r);

  ll ans = 0;
  rep(i, 4) chmax(ans, res[i][R][C]);
  print(ans);

  return 0;
}