Problem p02586 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> VI;
typedef vector<vector<int>> VVI;
typedef vector<ll> VLL;
typedef vector<vector<ll>> VVLL;
typedef pair<ll, ll> Pair;
template <class T> T input() {
  T t;
  cin >> t;
  return t;
}
#define FOR(i, a, b) for (ll i = a; i < b; i++)
#define REP(i, b) FOR(i, 0, b)
#define RFOR(i, a, b) for (ll i = a - 1; i >= b; i--)
#define RREP(i, a) RFOR(i, a, 0)
#define REPALL(i, x) for (ll i = 0; i < x.size(); i++)
#define RREPALL(i, x) for (ll i = x.size() - 1; i >= 0; i--)
#define REPITR(itr, x) for (auto itr = (x).begin(); itr != (x).end(); itr++)
#define ALL(x) (x).begin(), (x).end()
#define SORT(x) sort(ALL(x))
#define MIN_ELEMENT(x) min_element(ALL(x))
#define MAX_ELEMENT(x) max_element(ALL(x))
#define COUNT(x, num) count(ALL(x), num)
#define MEMSET(x, val) memset(x, val, sizeof(x))
#define CHMAX(a, b) a = max(a, b)
#define CHMIN(a, b) a = min(a, b)
#define FIND(x, key) x.find(key) != x.end()
#define IN_RANGE_V2(v, k, x, y)                                                \
  (0 <= x + dx[k] && x + dx[k] < v[y].size() && 0 <= y + dy[k] &&              \
   y + dy[k] < v.size())
#define debug(x) cerr << __LINE__ << ": " << (#x) << " = " << (x) << endl;
void YES(bool flag) { cout << (flag ? "YES" : "NO") << endl; }
void Yes(bool flag) { cout << (flag ? "Yes" : "No") << endl; }
void yes(bool flag) { cout << (flag ? "yes" : "no") << endl; }
#define PRINT_ARRAY_H(a)                                                       \
  REPALL(__i, a) { cout << a[__i] << (__i != a.size() - 1 ? " " : ""); }       \
  newline;
#define PRINT_ARRAY_V(a)                                                       \
  REPALL(__i, a) { cout << a[__i] << endl; }
#define e1 first
#define e2 second
#define newline putchar('\n')
#define cspace ' '
#define sspace " "
const int INF = 1e7;
const ll MOD = 1e9 + 7;
const double pi = 3.141592653589793;
const VI dx = {1, 0, -1, 0};
const VI dy = {0, 1, 0, -1};
// const VI dx = {1, 1, 0, -1, -1, -1, 0, 1};
// const VI dy = {0, 1, 1, 1, 0, -1, -1, -1};

VVLL values(3333, VLL(3333));
VVLL cval(3333, VLL(4));

void solve() {
  ll R, C, K;
  cin >> R >> C >> K;
  REP(i, K) {
    ll r, c, v;
    cin >> r >> c >> v;
    r--;
    c--;
    values[r][c] = v;
  }

  cval[0][1] = values[0][0];
  REP(i, R + C - 1) {
    VVLL tval(3333, VLL(4));
    REP(j, 3333) {
      ll k = i - j;
      if (k < 0)
        break;
      else if (k >= C)
        continue;

      REP(t, 4) {
        CHMAX(tval[j][t], cval[j][t]);
        if (t < 3)
          CHMAX(tval[j][t + 1], cval[j][t] + values[j][k + 1]);
        CHMAX(tval[j + 1][0], cval[j][t]);
        CHMAX(tval[j + 1][1], cval[j][t] + values[j + 1][k]);
      }
    }
    cval = tval;

    // cout<<i<<sspace<<*MAX_ELEMENT(cval[i])<<endl;
  }
  cout << *MAX_ELEMENT(cval[R]) << endl;
}

int main() {
  cout << fixed << setprecision(20);
  int __t = 1;
  // cin>>__t;
  REP(i, __t) { solve(); }
  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> VI;
typedef vector<vector<int>> VVI;
typedef vector<ll> VLL;
typedef vector<vector<ll>> VVLL;
typedef pair<ll, ll> Pair;
template <class T> T input() {
  T t;
  cin >> t;
  return t;
}
#define FOR(i, a, b) for (ll i = a; i < b; i++)
#define REP(i, b) FOR(i, 0, b)
#define RFOR(i, a, b) for (ll i = a - 1; i >= b; i--)
#define RREP(i, a) RFOR(i, a, 0)
#define REPALL(i, x) for (ll i = 0; i < x.size(); i++)
#define RREPALL(i, x) for (ll i = x.size() - 1; i >= 0; i--)
#define REPITR(itr, x) for (auto itr = (x).begin(); itr != (x).end(); itr++)
#define ALL(x) (x).begin(), (x).end()
#define SORT(x) sort(ALL(x))
#define MIN_ELEMENT(x) min_element(ALL(x))
#define MAX_ELEMENT(x) max_element(ALL(x))
#define COUNT(x, num) count(ALL(x), num)
#define MEMSET(x, val) memset(x, val, sizeof(x))
#define CHMAX(a, b) a = max(a, b)
#define CHMIN(a, b) a = min(a, b)
#define FIND(x, key) x.find(key) != x.end()
#define IN_RANGE_V2(v, k, x, y)                                                \
  (0 <= x + dx[k] && x + dx[k] < v[y].size() && 0 <= y + dy[k] &&              \
   y + dy[k] < v.size())
#define debug(x) cerr << __LINE__ << ": " << (#x) << " = " << (x) << endl;
void YES(bool flag) { cout << (flag ? "YES" : "NO") << endl; }
void Yes(bool flag) { cout << (flag ? "Yes" : "No") << endl; }
void yes(bool flag) { cout << (flag ? "yes" : "no") << endl; }
#define PRINT_ARRAY_H(a)                                                       \
  REPALL(__i, a) { cout << a[__i] << (__i != a.size() - 1 ? " " : ""); }       \
  newline;
#define PRINT_ARRAY_V(a)                                                       \
  REPALL(__i, a) { cout << a[__i] << endl; }
#define e1 first
#define e2 second
#define newline putchar('\n')
#define cspace ' '
#define sspace " "
const int INF = 1e7;
const ll MOD = 1e9 + 7;
const double pi = 3.141592653589793;
const VI dx = {1, 0, -1, 0};
const VI dy = {0, 1, 0, -1};
// const VI dx = {1, 1, 0, -1, -1, -1, 0, 1};
// const VI dy = {0, 1, 1, 1, 0, -1, -1, -1};

VVLL values(3333, VLL(3333));
VVLL cval(3333, VLL(4));

void solve() {
  ll R, C, K;
  cin >> R >> C >> K;
  REP(i, K) {
    ll r, c, v;
    cin >> r >> c >> v;
    r--;
    c--;
    values[r][c] = v;
  }

  cval[0][1] = values[0][0];
  REP(i, R + C - 1) {
    VVLL tval(3333, VLL(4));
    REP(j, R) {
      ll k = i - j;
      if (k < 0)
        break;
      else if (k >= C)
        continue;

      REP(t, 4) {
        CHMAX(tval[j][t], cval[j][t]);
        if (t < 3)
          CHMAX(tval[j][t + 1], cval[j][t] + values[j][k + 1]);
        CHMAX(tval[j + 1][0], cval[j][t]);
        CHMAX(tval[j + 1][1], cval[j][t] + values[j + 1][k]);
      }
    }
    cval = tval;

    // cout<<i<<sspace<<*MAX_ELEMENT(cval[i])<<endl;
  }
  cout << *MAX_ELEMENT(cval[R]) << endl;
}

int main() {
  cout << fixed << setprecision(20);
  int __t = 1;
  // cin>>__t;
  REP(i, __t) { solve(); }
  return 0;
}