Language: C++

#include<bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
#define all(x)(x).begin(), (x).end() // 昇順ソート
#define rall(v)(v).rbegin(), (v).rend() // 降順ソート
#define INF 1 LL << 60
typedef long long int LL;
typedef long long int ll;
#define pll pair < ll, ll >
#define F first
#define S second
const int MOD = 1000000007;
template < class T > bool chmax(T & a,const T & b) { if (a < b) { a = b; return true; } return false; }
template < class T > bool chmin(T & a,const T & b) { if (a > b) { a = b; return true; } return false; }
// 任意のlogは　対数の底の変換を使う    log(N) / log(任意の底)

int main() {
    LL N,K;cin >> N >> K;
    vector<LL> P(N);
    rep(i,N){
        LL tmp;cin >> tmp;
        P[i] = tmp -1;
    }
    vector<LL> C(N);
    rep(i,N)cin >> C[i];

    vector<LL> onecy_val(N);
    vector<LL> onecy_ct(N);

    rep(i,N){   // (N^2) で前処理
        LL tmp = C[P[i]];
        LL now = P[i];
        LL ct = 1;
        while(now != i){
            ct++;
            tmp += C[P[now]];
            now = P[now];
        }
        onecy_val[i] = tmp;
        onecy_ct[i] = ct;        
    }

  //  rep(i,N)cout << onecy_val[i] << " " << onecy_ct[i] << endl;
    LL ans = -100000000000000;
    rep(i,N){   // i はスタート地点
        LL val = onecy_val[i];
        LL ct = onecy_ct[i];
        LL tmp = 0;
        if(K > ct){
            if(val > 0){
                tmp += (K/ct)*val;
                int now = P[i];
                ans = max(ans,tmp);
                rep(j,K-(K/ct)*ct){
                    tmp += C[P[now]];
                    now = P[now];
                    ans = max(ans,tmp);
                }
            }
            else if(val <= 0){
                int now = P[i];
                rep(j,N){
                    tmp += C[P[now]];
                    now = P[now];
                    ans = max(ans,tmp);
                }
            }
        }
        else{
            int now = P[i];
            rep(j,K){
                tmp += C[P[now]];
                now = P[now];
                ans = max(ans,tmp);
            }            
        }
    }
    ans = max(ans,0);
    cout << ans << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:78:14: error: no matching function for call to 'max(LL&, int)'
   78 |     ans = max(ans,0);
      |           ~~~^~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:78:14: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   78 |     ans = max(ans,0);
      |           ~~~^~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:78:14: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   78 |     ans = max(ans,0);
      |           ~~~^~~~~~~