Language: C++

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define For(i,n,k) for(ll i=(n);i<(k);i++)
int main(){
    ll n,ik,ans=0;
    string s;
    cin>>n>>s;
    //s="";For(i,0,20) s+="qwertyuiopasdfghjklzxcvbnm";n=s.size();
    if(n<=1000){
        For(i,0,10) s+='*';
        For(i,1,1+n/2){
            map<string,ll> bubun;
            string k=s.substr(0,i);
            bubun[k]=i;
            For(j,i,n){
                k.erase(0,1);
                k+=s.at(j);
                ik=bubun[k];
                if(ik==0){
                    bubun[k]=j+1;
                }
                else if(ik+i<=j+1){
                    ans=i;
                    break;
                }
            }
            if(ans!=i){
                break;
            }
        }
        cout<<ans<<endl;
    }
    else{
        For(l,0,n) s+='*';
        ll kouho=n/4;
        bool flag=false;
        For(num,0,10){
            map<string,ll> bubun;
            string k=s.substr(0,kouho);
            bubun[k]=kouho;
            For(j,kouho,n){
                k.erase(0,1);
                k+=s.at(j);
                ik=bubun[k];
                if(ik==0){
                    bubun[k]=j+1;
                }
                else if(ik+kouho<=j+1){
                    flag=true;
                    break;
                }
            }
            ll div=pow(2,num+2);
            if(flag) kouho+=n/div;
            else kouho-=n/div;
        }
        ans=kouho;
        if(!flag) ans=max(ans-10,0);
        For(i,ans,1+n/2){
            map<string,ll> bubun;
            string k=s.substr(0,i);
            bubun[k]=i;
            For(j,i,n){
                k.erase(0,1);
                k+=s.at(j);
                ik=bubun[k];
                if(ik==0){
                    bubun[k]=j+1;
                }
                else if(ik+i<=j+1){
                    ans=i;
                    break;
                }
            }
            if(ans!=i){
                break;
            }
        }      
        cout<<ans<<endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:59:26: error: no matching function for call to 'max(ll, int)'
   59 |         if(!flag) ans=max(ans-10,0);
      |                       ~~~^~~~~~~~~~
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:59:26: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   59 |         if(!flag) ans=max(ans-10,0);
      |                       ~~~^~~~~~~~~~
/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:59:26: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   59 |         if(!flag) ans=max(ans-10,0);
      |                       ~~~^~~~~~~~~~