Language: C++

#include <iostream>
#include <sstream>
#include <string>
#include <algorithm>
#include <numeric>
#include <vector>
#include <list>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <iterator>
#include <cmath>

using namespace std;

void input(){}
template<class T,class...Ts>void input(T&a,Ts&...as){cin>>a;input(as...);}
template<class V>istream&operator>>(istream&i,vector<V>&a){for(auto&e:a)i>>e;return i;}

template<class T>void print(T &a){cout<<a<<endl;}
template<class T,class...Ts>void print(T&a,Ts&...as){cout<<a<<" ";print(as...);}
template<class F,class S>ostream&operator<<(ostream&o,pair<F,S>const&pair){return o<<"("<<pair.first<<"->"<<pair.second<<")";}
template<size_t I,size_t N,class...Ts>struct OutTuple;
template<>struct OutTuple<1,0>{ostream&operator()(ostream&o,tuple<>const&t){return o;}};
template<size_t N,class...Ts>struct OutTuple<N,N,Ts...>{ostream&operator()(ostream&o,tuple<Ts...>const&t){return o<<get<N-1>(t);}};
template<size_t I,size_t N,class...Ts>struct OutTuple{ostream&operator()(ostream&o,tuple<Ts...>const&t){return OutTuple<I+1,N,Ts...>{}(o<<get<I-1>(t)<<",",t);}};
template<class...Ts>ostream&operator<<(ostream&o,tuple<Ts...>const&t){return OutTuple<1,sizeof...(Ts),Ts...>{}(o<<"(",t)<<")";}
template<class C>ostream&outContainer(ostream&o,C const&a){o<<"[";for(auto i=a.begin(),e=a.end();i!=e;o<<((++i!=e)?",":""))o<<*i;return o<<"]";}
template<class V>ostream&operator<<(ostream&o,list<V>const&a){return outContainer(o, a);}
template<class V>ostream&operator<<(ostream&o,vector<V>const&a){return outContainer(o, a);}
template<class V>ostream&operator<<(ostream&o,set<V>const&a){return outContainer(o, a);}
template<class V>ostream&operator<<(ostream&o,unordered_set<V>const&a){return outContainer(o, a);}
template<class K,class V>ostream&operator<<(ostream&o,map<K,V>const&a){return outContainer(o, a);}
template<class K,class V>ostream&operator<<(ostream&o,unordered_map<K,V>const&a){return outContainer(o, a);}

template<size_t I,size_t N,class...Ts>struct Hash;
template<>struct Hash<1,0>{size_t operator()(size_t h,tuple<>const&t){return h;}};
template<size_t N,class...Ts>struct Hash<N,N,Ts...>{size_t operator()(size_t h,tuple<Ts...>const&t){auto e=get<N-1>(t);return h*31+hash<decltype(e)>{}(e);}};
template<size_t I,size_t N,class...Ts>struct Hash{size_t operator()(size_t h,tuple<Ts...>const&t){auto e=get<I-1>(t);return Hash<I+1,N,Ts...>{}(h*31+hash<decltype(e)>{}(e),t);}};
template<class...Ts>size_t compute_hash(tuple<Ts...>const&t){return Hash<1,sizeof...(Ts),Ts...>{}(17,t);}
namespace std{template<class...Ts>struct hash<tuple<Ts...>>{size_t operator()(tuple<Ts...>const&t)const{return compute_hash(t);}};}

using lli = long long int;
lli gcd(lli const p, lli const q) { return q == 0 ? p : gcd(q, p%q); }
lli pow(lli const a, lli const n, lli const m){return(!n)?1:(n&1)?(((a%m)*pow(a,n-1,m))%m):[=](){lli b=pow(a,n/2,m);return(b*b)%m;}();}
lli inv(lli const a, lli const p) { return pow(a, p-2, p); }
constexpr lli MOD = 1e9+7;

int main(){
  lli N;
  input(N);
  using T=tuple<lli,lli>;
  vector<lli> xs(N);
  input(xs);
  vector<lli> ys(N);
  input(ys);
  unordered_map<T,lli> pq;
  for (size_t i = 0; i < N; ++i) {
    for (size_t j = i+1; j < N; ++j) {
      T a = {xs[i] - xs[j], ys[i] - ys[j]};
      pq[a] = (pq.find(a) == pq.end()) ? 1 : (pq[a] + 1);
    }
  }
  auto found = max_element(pq.begin(), pq.end(), [](auto const &a,auto const &b){ return a.second < b.second; });
  if (found == pq.end()) {
    auto ans = 1;
    print(ans);
  }
  else {
    print(found->second);
  }
  
  
}

Compiler output:
a.cc: In instantiation of 'void input(T&, Ts& ...) [with T = std::vector<long long int>; Ts = {}]':
a.cc:55:8:   required from here
   55 |   input(xs);
      |   ~~~~~^~~~
a.cc:18:57: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'std::vector<long long int>')
   18 | template<class T,class...Ts>void input(T&a,Ts&...as){cin>>a;input(as...);}
      |                                                      ~~~^~~
In file included from /usr/include/c++/14/iostream:42,
                 from a.cc:1:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:24: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'bool&'
  170 |       operator>>(bool& __n)
      |                  ~~~~~~^~~
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]'
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:25: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'short int&'
  174 |       operator>>(short& __n);
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:34: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'short unsigned int&'
  177 |       operator>>(unsigned short& __n)
      |                  ~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]'
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:23: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'int&'
  181 |       operator>>(int& __n);
      |                  ~~~~~^~~
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:32: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'unsigned int&'
  184 |       operator>>(unsigned int& __n)
      |                  ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:24: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'long int&'
  188 |       operator>>(long& __n)
      |                  ~~~~~~^~~
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:33: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'long unsigned int&'
  192 |       operator>>(unsigned long& __n)
      |                  ~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:29: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'long long int&'
  199 |       operator>>(long long& __n)
      |                  ~~~~~~~~~~~^~~
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:38: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'long long unsigned int&'
  203 |       operator>>(unsigned long long& __n)
      |                  ~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:25: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'float&'
  219 |       operator>>(float& __f)
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:26: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'double&'
  223 |       operator>>(double& __f)
      |                  ~~~~~~~~^~~
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:31: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'long double&'
  227 |       operator>>(long double& __f)
      |                  ~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:25: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'void*&'
  328 |       operator>>(void*& __p)
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:36: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'}
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |                  ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/istream:126:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>; __ios_type = std::basic_ios<char>]'
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:126:32: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'}
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |                  ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
/usr/include/c++/14/istream:133:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  133 |       operator>>(ios_base& (*__pf)(ios_base&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:133:30: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'std::ios_base& (*)(std::ios_base&)'
  133 |       operator>>(ios_base& (*__pf)(ios_base&))
      |                  ~~~~~~~~~~~~^~~~~~~~~~~~~~~~
/usr/include/c++/14/istream:352:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(__streambuf_type*) [with _CharT = char; _Traits = std::char_traits<char>; __streambuf_type = std::basic_streambuf<char>]'
  352 |       operator>>(__streambuf_type* __sb);
      |       ^~~~~~~~
/usr/include/c++/14/istream:352:36: note:   no known conversion for argument 1 from 'std::vector<long long int>' to 'std::basic_istream<char>::__streambuf_type*' {aka 'std::basic_streambuf<char>*'}
  352 |       operator>>(__streambuf_type* __sb);
      |