Language: C++

#include<bits/stdc++.h> //Ithea Myse Valgulious
namespace chtholly{
typedef long long ll;
#define re0 register int
#define rel register ll
#define rec register char
#define gc getchar
//#define gc() (p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<23,stdin),p1==p2)?-1:*p1++)
#define pc putchar
#define p32 pc(' ')
#define pl puts("")
/*By Citrus*/
char buf[1<<23],*p1=buf,*p2=buf;
inline int read(){
  int x=0,f=1;char c=gc();
  for (;!isdigit(c);c=gc()) f^=c=='-';
  for (;isdigit(c);c=gc()) x=(x<<3)+(x<<1)+(c^'0');
  return f?x:-x;
  }
template <typename mitsuha>
inline bool read(mitsuha &x){
  x=0;int f=1;char c=gc();
  for (;!isdigit(c)&&~c;c=gc()) f^=c=='-';
  if (!~c) return 0;
  for (;isdigit(c);c=gc()) x=(x<<3)+(x<<1)+(c^'0');
  return x=f?x:-x,1;
  }
template <typename mitsuha>
inline int write(mitsuha x){
  if (!x) return 0&pc(48);
  if (x<0) pc('-'),x=-x;
  int bit[20],i,p=0;
  for (;x;x/=10) bit[++p]=x%10;
  for (i=p;i;--i) pc(bit[i]+48);
  return 0;
  }
inline char fuhao(){
  char c=gc();
  for (;isspace(c);c=gc());
  return c;
  }
}using namespace chtholly;
using namespace std;
const int yuzu=1e5;
typedef int fuko[yuzu|10];
typedef ll azusa[yuzu|10];
fuko p,c;

int main() {
  int i,j,n,k;
  read(n),read(k);
  for (i=1;i<=n;++i) p[i]=read();
  for (j=1;j<=n;++j) c[j]=read();
  ll ans=-2e9;
  for (i=1;i<=n;++i) {
    vector<ll> v;
    ll tmp=c[i];
    v.push_back(c[i]);
    for (j=p[i];j^i;j=p[j]) v.push_back(tmp+=c[j]);
    for (j=0;j<v.size();++j) {
      ll res=k-j-1;
      if (res<0) break;
      ans=max(ans,v[j]+res/v.size()*max(tmp,0ll));
    }
  }
  cout<<ans<<'\n';
}

Compiler output:
a.cc: In function 'int main()':
a.cc:63:14: error: no matching function for call to 'max(chtholly::ll&, long long unsigned int)'
   63 |       ans=max(ans,v[j]+res/v.size()*max(tmp,0ll));
      |           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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:63:14: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'long long unsigned int')
   63 |       ans=max(ans,v[j]+res/v.size()*max(tmp,0ll));
      |           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/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:63:14: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   63 |       ans=max(ans,v[j]+res/v.size()*max(tmp,0ll));
      |           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~