Problem p02585 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>

#define CHOOSE(a) CHOOSE2 a
#define CHOOSE2(a0, a1, a2, a3, a4, x, ...) x
#define dump_1(x1) cerr << #x1 << ": " << x1 << endl
#define dump_2(x1, x2)                                                         \\
  cerr << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << endl
#define dump_3(x1, x2, x3)                                                     \\
  cerr << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "      \\
       << x3 << endl
#define dump_4(x1, x2, x3, x4)                                                 \\
  cerr << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "      \\
       << x3 << ", " #x4 << ": " << x4 << endl
#define dump_5(x1, x2, x3, x4, x5)                                             \\
  cerr << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "      \\
       << x3 << ", " #x4 << ": " << x4 << ", " #x5 << ": " << x5 << endl
#define dump(...)                                                              \\
  CHOOSE((__VA_ARGS__, dump_5, dump_4, dump_3, dump_2, dump_1, ~))(__VA_ARGS__)
#define check(s) cerr << s << endl

#define rep(i, n) for (int i = 0; i < n; i++)
#define repr(i, n) for (int i = n; i >= 0; i--)
#define FOR(i, m, n) for (int i = m; i < n; i++)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define unique(v) v.erase(unique(v.begin(), v.end()), v.end());
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)

using namespace std;

using ll = long long;

vector<int> dx = {0, 1, 0, -1};
vector<int> dy = {1, 0, -1, 0};

const ll LINF = 2e18;
const int INF = 1e9;
ll N;
ll K;
std::vector<ll> P;
std::vector<ll> C;

void solve() {
  ll ans = -1e18;

  rep(i, N) {
    int x = i;
    vector<ll> s;
    ll tot = 0;
    while (1) {
      x = P.at(x);
      s.push_back(C.at(x));
      tot += C.at(x);
      if (x == i)
        break;
    }
    int l = s.size();
    ll t = 0;
    rep(j, l) {
      t += s.at(j);
      if (j + 1 > K)
        break;
      ll now = t;
      if (tot > 0) {
        ll e = (K - (j + 1)) / l;
        now += tot * e;
      }

      ans = max(ans, now);
    }
  }

  cout << ans << endl;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  scanf("%lld", &N);
  scanf("%lld", &K);
  P.resize(N);
  C.resize(N);
  for (int i = 0; i < N; i++) {
    scanf("%lld", &P[i]);
    P.at(i)--; // 0-indexed
  }
  for (int i = 0; i < N; i++) {
    scanf("%lld", &C[i]);
  }
  solve();
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>

#define CHOOSE(a) CHOOSE2 a
#define CHOOSE2(a0, a1, a2, a3, a4, x, ...) x
#define dump_1(x1) cerr << #x1 << ": " << x1 << endl
#define dump_2(x1, x2)                                                         \\
  cerr << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << endl
#define dump_3(x1, x2, x3)                                                     \\
  cerr << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "      \\
       << x3 << endl
#define dump_4(x1, x2, x3, x4)                                                 \\
  cerr << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "      \\
       << x3 << ", " #x4 << ": " << x4 << endl
#define dump_5(x1, x2, x3, x4, x5)                                             \\
  cerr << #x1 << ": " << x1 << ", " #x2 << ": " << x2 << ", " #x3 << ": "      \\
       << x3 << ", " #x4 << ": " << x4 << ", " #x5 << ": " << x5 << endl
#define dump(...)                                                              \\
  CHOOSE((__VA_ARGS__, dump_5, dump_4, dump_3, dump_2, dump_1, ~))(__VA_ARGS__)
#define check(s) cerr << s << endl

#define rep(i, n) for (int i = 0; i < n; i++)
#define repr(i, n) for (int i = n; i >= 0; i--)
#define FOR(i, m, n) for (int i = m; i < n; i++)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define unique(v) v.erase(unique(v.begin(), v.end()), v.end());
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)

using namespace std;

using ll = long long;

vector<int> dx = {0, 1, 0, -1};
vector<int> dy = {1, 0, -1, 0};

const ll LINF = 2e18;
const int INF = 1e9;
ll N;
ll K;
std::vector<ll> P;
std::vector<ll> C;

ll f(int s) {
  int p = P.at(s);
  ll ans = C.at(p);
  ll cur = 0;

  rep(i, K) {
    cur += C.at(p);
    p = P.at(p);
    chmax(ans, cur);
  }

  return ans;
}

void solve() {
  ll ans = f(0);

  rep(i, N) { chmax(ans, f(i)); }

  cout << ans << endl;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  scanf("%lld", &N);
  scanf("%lld", &K);
  P.resize(N);
  C.resize(N);
  for (int i = 0; i < N; i++) {
    scanf("%lld", &P[i]);
    P.at(i)--; // 0-indexed
  }
  for (int i = 0; i < N; i++) {
    scanf("%lld", &C[i]);
  }
  solve();
  return 0;
}