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

#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp>
using namespace std;
using bint = boost::multiprecision::cpp_int;
using ll = long long;
using pint = pair<int, int>;
using pll = pair<ll, ll>;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define repSE(i, s, n) for (int i = (s); i < (n); i++)
#define rrepSE(i, s, e) for (int i = (s); i > (e); i--)
#define ssort(v) sort(v.begin(), v.end())
#define gsort(v) sort(v.rbegin(), v.rend())
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (auto &v : vec)
    is >> v;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  os << "[";
  for (auto v : vec)
    os << v << ",";
  os << "]";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const deque<T> &vec) {
  os << "deq[";
  for (auto v : vec)
    os << v << ",";
  os << "]";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &vec) {
  os << "{";
  for (auto v : vec)
    os << v << ",";
  os << "}";
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const unordered_set<T> &vec) {
  os << "{";
  for (auto v : vec)
    os << v << ",";
  os << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &vec) {
  os << "{";
  for (auto v : vec)
    os << v << ",";
  os << "}";
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const unordered_multiset<T> &vec) {
  os << "{";
  for (auto v : vec)
    os << v << ",";
  os << "}";
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &pa) {
  os << "(" << pa.first << "," << pa.second << ")";
  return os;
}
template <typename TK, typename TV>
ostream &operator<<(ostream &os, const map<TK, TV> &mp) {
  os << "{";
  for (auto v : mp)
    os << v.first << "=>" << v.second << ",";
  os << "}";
  return os;
}
template <typename TK, typename TV>
ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp) {
  os << "{";
  for (auto v : mp)
    os << v.first << "=>" << v.second << ",";
  os << "}";
  return os;
}
template <typename T> bool chmax(T &m, const T q) {
  if (m < q) {
    m = q;
    return true;
  } else
    return false;
}
template <typename T> bool chmin(T &m, const T q) {
  if (q < m) {
    m = q;
    return true;
  } else
    return false;
}
#define DEBUG_PRINT(var) std::cout << #var << " = " << var << "\\n";

const ll MX = ll(1e18);

int main() {
  ll n, k;
  cin >> n >> k;
  vector<int> p(n);
  vector<ll> c(n);
  rep(i, n) {
    cin >> p[i];
    p[i]--;
  }
  rep(i, n) cin >> c[i];
  ll ans = -MX;
  rep(i, n) {
    ll sum = 0;
    int start = i, cur = i;
    cur = p[cur];
    sum += c[cur];
    ll cnt = 1;
    while (cur != start) {
      cur = p[cur];
      sum += c[cur];
      cnt++;
    }
    cur = start;
    ll cnt2mx = 0;
    ll accum = 0;
    while (true) {
      cnt2mx++;
      accum += c[cur];
      if (cnt2mx > k)
        break;
      ll num = (k - cnt2mx) / cnt;
      ll score = accum + max(0ll, sum) * num;
      chmax(ans, score);
      cur = p[cur];
      if (cur == start)
        break;
    }
    // cout << "i: " << i << ", cnt: " << cnt << ", mx: " << mx << ", sum: " <<
    // sum
    //      << ", cnt2mx: " << cnt2mx << endl;
  }
  cout << ans << "\\n";
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp>
using namespace std;
using bint = boost::multiprecision::cpp_int;
using ll = long long;
using pint = pair<int, int>;
using pll = pair<ll, ll>;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define repSE(i, s, n) for (int i = (s); i < (n); i++)
#define rrepSE(i, s, e) for (int i = (s); i > (e); i--)
#define ssort(v) sort(v.begin(), v.end())
#define gsort(v) sort(v.rbegin(), v.rend())
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (auto &v : vec)
    is >> v;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  os << "[";
  for (auto v : vec)
    os << v << ",";
  os << "]";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const deque<T> &vec) {
  os << "deq[";
  for (auto v : vec)
    os << v << ",";
  os << "]";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &vec) {
  os << "{";
  for (auto v : vec)
    os << v << ",";
  os << "}";
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const unordered_set<T> &vec) {
  os << "{";
  for (auto v : vec)
    os << v << ",";
  os << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &vec) {
  os << "{";
  for (auto v : vec)
    os << v << ",";
  os << "}";
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const unordered_multiset<T> &vec) {
  os << "{";
  for (auto v : vec)
    os << v << ",";
  os << "}";
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &pa) {
  os << "(" << pa.first << "," << pa.second << ")";
  return os;
}
template <typename TK, typename TV>
ostream &operator<<(ostream &os, const map<TK, TV> &mp) {
  os << "{";
  for (auto v : mp)
    os << v.first << "=>" << v.second << ",";
  os << "}";
  return os;
}
template <typename TK, typename TV>
ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp) {
  os << "{";
  for (auto v : mp)
    os << v.first << "=>" << v.second << ",";
  os << "}";
  return os;
}
template <typename T> bool chmax(T &m, const T q) {
  if (m < q) {
    m = q;
    return true;
  } else
    return false;
}
template <typename T> bool chmin(T &m, const T q) {
  if (q < m) {
    m = q;
    return true;
  } else
    return false;
}
#define DEBUG_PRINT(var) std::cout << #var << " = " << var << "\\n";

const ll MX = ll(1e18);

int main() {
  ll n, k;
  cin >> n >> k;
  vector<int> p(n);
  vector<ll> c(n);
  rep(i, n) {
    cin >> p[i];
    p[i]--;
  }
  rep(i, n) cin >> c[i];
  ll ans = -MX;
  rep(i, n) {
    ll sum = 0;
    int start = i, cur = i;
    cur = p[cur];
    sum += c[cur];
    ll cnt = 1;
    while (cur != start) {
      cur = p[cur];
      sum += c[cur];
      cnt++;
    }
    cur = start;
    ll cnt2mx = 0;
    ll accum = 0;
    while (true) {
      cnt2mx++;
      accum += c[cur];
      if (cnt2mx > k)
        break;
      ll num = (k - cnt2mx) / cnt;
      ll score = accum + max(0ll, sum) * num;
      chmax(ans, score);
      cur = p[cur];
    }
    // cout << "i: " << i << ", cnt: " << cnt << ", mx: " << mx << ", sum: " <<
    // sum
    //      << ", cnt2mx: " << cnt2mx << endl;
  }
  cout << ans << "\\n";
  return 0;
}