Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
#define FOR(NAME, START, NUM) for (ll NAME = START; NAME < (NUM); NAME++)
#define REP(NAME, NUM) for (ll NAME = 0; NAME < (NUM); NAME++)
#define BREP(NAME, NUM) for (ll NAME = (NUM)-1; NAME >= 0; NAME--)
#define ALL(NAME) (NAME).begin(), (NAME).end()
const ll INF = 1000000000000000;

string s;
int main(){
	ll  n, x, y, sumx = 0, sumy = 0;
	long double max = 0;
	cin >> n;
	vector<pair<ll,ll>> p(8);

	p[0].first = 0;
	p[0].second = 0;
	p[1].first = 0;
	p[1].second = 0;
	p[2].first = 0;
	p[2].second = 0;
	p[3].first = 0;
	p[3].second = 0;
	p[4].first = 0;
	p[4].second = 0;
	p[5].first = 0;
	p[5].second = 0;
	p[6].first = 0;
	p[6].second = 0;
	p[7].first = 0;
	p[7].second = 0;

	REP(i, n){
		cin >> x >> y;
		if(x > 0 && y > 0){p[0].first+=x; p[0].second+=y;}
		if(x > 0 && y < 0){p[1].first+=x; p[1].second+=y;}
		if(x < 0 && y > 0){p[2].first+=x; p[2].second+=y;}
		if(x < 0 && y < 0){p[3].first+=x; p[3].second+=y;}
		if(x == 0 && y > 0){p[4].first+=x; p[4].second+=y;}
		if(x == 0 && y < 0){p[5].first+=x; p[5].second+=y;}
		if(x > 0 && y == 0){p[6].first+=x; p[6].second+=y;}
		if(x < 0 && y == 0){p[7].first+=x; p[7].second+=y;}
	}

	REP(i, 2){
		REP(j, 2){
			REP(k, 2){
				REP(l, 2){
					REP(m, 2){
						REP(n, 2){
							REP(o, 2){
								REP(q, 2){
									if(i == 1){sumx += p[0].first; sumy  += p[0].second;}
									if(j == 1){sumx += p[1].first; sumy  += p[1].second;}
									if(k == 1){sumx += p[2].first; sumy  += p[2].second;}
									if(l == 1){sumx += p[3].first; sumy  += p[3].second;}
									if(m == 1){sumx += p[4].first; sumy  += p[4].second;}
									if(n == 1){sumx += p[5].first; sumy  += p[5].second;}
									if(o == 1){sumx += p[6].first; sumy  += p[6].second;}
									if(p == 1){sumx += p[7].first; sumy  += p[7].second;}

									if(max < sumx*sumx + sumy*sumy){max = sumx*sumx + sumy*sumy;}

									sumx = 0; sumy = 0;
								}
							}
						}
					}
				}
			}
		}
	}

	max = pow(max, 0.5);

	cout << fixed << setprecision(10);

	cout << max << endl;

}


Compiler output:
a.cc: In function 'int main()':
a.cc:63:78: error: no match for 'operator==' (operand types are 'std::vector<std::pair<long long int, long long int> >' and 'int')
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                            ~ ^~ ~
      |                                                                            |    |
      |                                                                            |    int
      |                                                                            std::vector<std::pair<long long int, long long int> >
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/bits/regex.h:1103:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1103 |     operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1103:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/regex.h:1199:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1199 |     operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1199:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/regex.h:1274:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1274 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1274:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/regex.h:1366:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1366 |     operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1366:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/regex.h:1441:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1441 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1441:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/regex.h:1534:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1534 |     operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1534:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/regex.h:1613:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1613 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1613:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/regex.h:2186:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator==(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2186 |     operator==(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2186:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_pair.h:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::pair<_T1, _T2>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::reverse_iterator<_Iterator>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::reverse_iterator<_Iterator>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
a.cc:63:81: note:   'std::vector<std::pair<long long int, long long int> >' is not derived from 'const std::move_iterator<_IteratorL>'
   63 |                                                                         if(p == 1){sumx += p[7].first; sumy  += p[7].second;}
      |                                                                                 ^
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(cons