Problem p02586 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (ll i = 0; i < n; i++)
#define repl(i, l, r) for (ll i = (l); i < (r); i++)
#define per(i, n) for (ll i = n - 1; i >= 0; i--)
#define perl(i, r, l) for (ll i = r - 1; i >= l; i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x, vector<x>, greater<x>>
#define all(x) (x).begin(), (x).end()
#define CST(x) cout << fixed << setprecision(x)
#define vtpl(x, y, z) vector<tuple<x, y, z>>
#define rev(x) reverse(x);
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using pl = pair<ll, ll>;
using vpl = vector<pl>;
using vvpl = vector<vpl>;
const ll MOD = 1000000007;
const ll MOD9 = 998244353;
const int inf = 1e9 + 10;
const ll INF = 4e18;
const ll dy[9] = {1, 0, -1, 0, 1, 1, -1, -1, 0};
const ll dx[9] = {0, -1, 0, 1, 1, -1, 1, -1, 0};
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
ll dp[3010][3010][4];
ll it[3010][3010];
int main() {
  ll r, c, pp;
  cin >> r >> c >> pp;
  map<pl, ll> mp;
  rep(i, pp) {
    ll a, b, c;
    cin >> a >> b >> c;
    a--;
    b--;
    it[a][b] = c;
  }
  rep(i, 3010) rep(j, 3010) rep(k, 4) dp[i][j][k] = -1;
  dp[0][0][0] = 0;
  rep(i, r) {
    rep(j, c) {
      rep(k, 4) {
        if (dp[i][j][k] == -1)
          continue;
        if (k <= 2)
          chmax(dp[i + 1][j][0], dp[i][j][k] + it[i][j]);
        chmax(dp[i + 1][j][0], dp[i][j][k]);
        if (k + 1 <= 3)
          chmax(dp[i][j + 1][k + 1], dp[i][j][k] + it[i][j]);
        chmax(dp[i][j + 1][k], dp[i][j][k]);
      }
    }
  }
  ll ans = 0;
  rep(j, 4) chmax(ans, dp[r - 1][c][j]);
  rep(j, 4) chmax(ans, dp[r][c - 1][j]);
  // rep(j,4)chmax(ans,dp[r-1][c-1][j]);
  cout << ans << endl;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (ll i = 0; i < n; i++)
#define repl(i, l, r) for (ll i = (l); i < (r); i++)
#define per(i, n) for (ll i = n - 1; i >= 0; i--)
#define perl(i, r, l) for (ll i = r - 1; i >= l; i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x, vector<x>, greater<x>>
#define all(x) (x).begin(), (x).end()
#define CST(x) cout << fixed << setprecision(x)
#define vtpl(x, y, z) vector<tuple<x, y, z>>
#define rev(x) reverse(x);
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using pl = pair<ll, ll>;
using vpl = vector<pl>;
using vvpl = vector<vpl>;
const ll MOD = 1000000007;
const ll MOD9 = 998244353;
const int inf = 1e9 + 10;
const ll INF = 4e18;
const ll dy[9] = {1, 0, -1, 0, 1, 1, -1, -1, 0};
const ll dx[9] = {0, -1, 0, 1, 1, -1, 1, -1, 0};
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
ll dp[3010][3010][4];
int main() {
  ll r, c, pp;
  cin >> r >> c >> pp;
  map<pl, ll> mp;
  rep(i, pp) {
    ll a, b, c;
    cin >> a >> b >> c;
    a--;
    b--;
    mp[{a, b}] = c;
  }
  rep(i, 3010) rep(j, 3010) rep(k, 4) dp[i][j][k] = -1;
  dp[0][0][0] = 0;
  rep(i, r) {
    rep(j, c) {
      rep(k, 4) {
        if (dp[i][j][k] == -1)
          continue;
        if (k <= 2)
          chmax(dp[i + 1][j][0], dp[i][j][k] + mp[{i, j}]);
        chmax(dp[i + 1][j][0], dp[i][j][k]);
        if (k + 1 <= 3)
          chmax(dp[i][j + 1][k + 1], dp[i][j][k] + mp[{i, j}]);
        chmax(dp[i][j + 1][k], dp[i][j][k]);
      }
    }
  }
  ll ans = 0;
  rep(j, 4) chmax(ans, dp[r - 1][c][j]);
  rep(j, 4) chmax(ans, dp[r][c - 1][j]);
  // rep(j,4)chmax(ans,dp[r-1][c-1][j]);
  cout << ans << endl;
}