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

/*
これを入れて実行
g++ code.cpp
./a.out
 */

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <stdio.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define all(x) (x).begin(), (x).end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;
typedef long long ll;
typedef long double ld;

int dy4[4] = {-1, 0, +1, 0};
int dx4[4] = {0, +1, 0, -1};
int dy8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dx8[8] = {0, 1, 1, 1, 0, -1, -1, -1};

const long long INF = 1LL << 60;
const ll MOD = 1e9 + 7;

bool greaterSecond(const pair<int, int> &f, const pair<int, int> &s) {
  return f.second > s.second;
}

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

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

ll conbinationMemo[100][100];

void cmemoInit() {
  rep(i, 100) {
    rep(j, 100) { conbinationMemo[i][j] = -1; }
  }
}

ll nCr(ll n, ll r) {
  if (conbinationMemo[n][r] != -1)
    return conbinationMemo[n][r];
  if (r == 0 || r == n) {
    return 1;
  } else if (r == 1) {
    return n;
  }
  return conbinationMemo[n][r] = (nCr(n - 1, r) + nCr(n - 1, r - 1));
}

ll nPr(ll n, ll r) {
  r = n - r;
  ll ret = 1;
  for (ll i = n; i >= r + 1; i--)
    ret *= i;
  return ret;
}
//-----------------------ここから-----------
ll R, C, K;
ll a[3030][3030] = {0};
ll memo[3030][3030][4];
ll rec(ll i, ll j, ll k) {
  if (i >= R || j >= C)
    return 0;
  if (memo[i][j][k] != -1)
    return memo[i][j][k];
  ll res = 0;

  if (k + 1 <= 3)
    res = max(res, rec(i + 1, j, 0) + a[i][j]);
  if (k + 1 <= 3)
    res = max(res, rec(i, j + 1, k + 1) + a[i][j]);

  res = max(res, rec(i + 1, j, 0));
  res = max(res, rec(i, j + 1, k));

  return memo[i][j][k] = res;
}
int main(void) {
  cin >> R >> C >> K;
  rep(i, K) {
    ll r, c, v;
    cin >> r >> c >> v;
    r--, c--;
    a[r][c] = v;
  }

  rep(i, 3030) rep(j, 3030) rep(k, 4) memo[i][j][k] = -1;

  cout << rec(0, 0, 0) << endl;
}

Error: TLE

Fixed submission:

/*
これを入れて実行
g++ code.cpp
./a.out
 */

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <stdio.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define all(x) (x).begin(), (x).end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;
typedef long long ll;
typedef long double ld;

int dy4[4] = {-1, 0, +1, 0};
int dx4[4] = {0, +1, 0, -1};
int dy8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dx8[8] = {0, 1, 1, 1, 0, -1, -1, -1};

const long long INF = 1LL << 60;
const ll MOD = 1e9 + 7;

bool greaterSecond(const pair<int, int> &f, const pair<int, int> &s) {
  return f.second > s.second;
}

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

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

ll conbinationMemo[100][100];

void cmemoInit() {
  rep(i, 100) {
    rep(j, 100) { conbinationMemo[i][j] = -1; }
  }
}

ll nCr(ll n, ll r) {
  if (conbinationMemo[n][r] != -1)
    return conbinationMemo[n][r];
  if (r == 0 || r == n) {
    return 1;
  } else if (r == 1) {
    return n;
  }
  return conbinationMemo[n][r] = (nCr(n - 1, r) + nCr(n - 1, r - 1));
}

ll nPr(ll n, ll r) {
  r = n - r;
  ll ret = 1;
  for (ll i = n; i >= r + 1; i--)
    ret *= i;
  return ret;
}
//-----------------------ここから-----------
ll R, C, K;
map<pair<ll, ll>, vector<ll>> mp;
ll memo[3030][3030][4];
ll rec(ll i, ll j, ll k) {
  if (i >= R || j >= C)
    return 0;
  if (memo[i][j][k] != -1)
    return memo[i][j][k];
  ll res = 0;
  ll sum = 0;
  for (ll ii = 0; ii < mp[{i, j}].size(); ii++) {
    sum += mp[{i, j}][ii];
    if (k + ii + 1 <= 3)
      res = max(res, rec(i + 1, j, 0) + sum);
    if (k + ii + 1 <= 3)
      res = max(res, rec(i, j + 1, k + ii + 1) + sum);
  }
  res = max(res, rec(i + 1, j, 0));
  res = max(res, rec(i, j + 1, k));

  return memo[i][j][k] = res;
}
int main(void) {
  cin >> R >> C >> K;
  rep(i, K) {
    ll r, c, v;
    cin >> r >> c >> v;
    r--, c--;
    mp[{r, c}].push_back(v);
  }

  for (auto &i : mp) {
    sort(all(i.second), greater<ll>());
  }

  rep(i, 3030) rep(j, 3030) rep(k, 4) memo[i][j][k] = -1;

  cout << rec(0, 0, 0) << endl;
}