Submission #938021

#TimeUsernameProblemLanguageResultExecution timeMemory
938021mat_jur다리 (APIO19_bridges)C++17
Compilation error
0 ms0 KiB
#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
auto&operator<<(auto &o, pair<auto, auto> p) {o << "(" << p.first << ", " << p.second << ")"; return o;}
auto operator<<(auto &o, auto x)->decltype(x.end(), o) {o<<"{"; for(auto e : x) o<<e<<", "; return o<<"}";}
#define debug(X) cerr << "["#X"]: " << X << '\n';
#else 
#define cerr if(0)cout
#define debug(X) ;
#endif
#define ll long long
#define all(v) (v).begin(), (v).end()
#define ssize(x) int(x.size())
#define fi first
#define se second
#define mp make_pair
#define eb emplace_back

struct dynamicUF {
	vector<int> e;
	dynamicUF(int n): e(n, -1) {}
	stack<array<int, 3>> s;

	int get(int a) {return e[a] < 0 ? a : get(e[a]);}

	int unionn(int a, int b) {
		a = get(a); b = get(b);
		if(a == b) return 0;
		if(e[a] > e[b]) swap(a, b);
		cerr << "ADD " << a << ' ' << b << '\n';
		s.push({a, b, e[a]});
		e[b] += e[a];
		e[a] = b;
		return 1;
	}

	void roll_back(int m = 1) {
		while (m--) {
			auto [a, b, sz] = s.top();
			s.pop();
			cerr << "UNDO " << a << ' ' << b << '\n';
			e[b] -= sz;
			e[a] = sz;
		}
	}
};

int main() {
	ios_base::sync_with_stdio(false); cin.tie(nullptr);

	int n, m;
	cin >> n >> m;
	vector<int> w(m), u(m), v(m);
	for(int i = 0; i < m; ++i) {
		cin >> u[i] >> v[i] >> w[i];
		u[i]--; v[i]--;
	}

	int q;
	cin >> q;

	vector<int> ans(q, -1);
//	const int B = 320;
	const int B = 1e9;
	vector<array<int, 4>> ev;
	vector<bool> changed(m);
	vector<array<int, 3>> upd;

	auto clean = [&] {
		debug(upd);
		debug(changed);
		debug(ev);

		dynamicUF sp(n);
		for(int i = 0; i < m; ++i) {
			if(!changed[i]) {ev.eb((array<int, 4>){w[i], u[i], v[i], 0}); changed[i] = false;}
		}
		sort(all(ev), [&](array<int, 4> x, array<int, 4> y) {
			if (x[0] != y[0]) return x[0] > y[0];
			return x[3] < y[3];
		});
		debug(ev);

		for(auto [d, a, b, c] : ev) {
			if(c == 0) {
				sp.unionn(a, b);
			}	
			else {
				cerr << "QUERY " << b << ' ' << mp(a, d) << '\n';
				debug(sp.e);
				map<int, int> M;
				for(auto [idx, r, t] : upd) {
					if(t <= b) M[idx] = r;
					else if(M[idx] == 0) M[idx] = w[idx];
				}
				
				int cnt = 0;
				for(auto [idx, r] : M) {
					if(r >= d) cnt += sp.unionn(u[idx], v[idx]);
				}

				cerr << "ANS \n";
				debug(cnt);
				debug(sp.e);
				ans[b] = -sp.e[sp.get(a)];
				cerr << "ROLL_BACK \n";
				sp.roll_back(cnt);
			}
		}

		for(auto [idx, r, t] : upd) {
			w[idx] = r;
		}
		upd.clear();
		ev.clear();
	};

	for(int t = 0; t < q; ++t) {
		int c;
		cin >> c;
		if(c == 1) {
			int b, r;
			cin >> b >> r;
			b--;
			changed[b] = true;
			upd.eb((array<int, 3>){b, r, t});
		}
		else {
			int d, s;
			cin >> s >> d;
			s--;
			ev.eb((array<int, 4>){d, s, t, 1});
		}
		if(t%B == B-1) {
			clean();
		}
	}
	clean();

	debug(ans);
	for(int i = 0; i < q; i++) if(ans[i] > -1) cout << ans[i] << '\n';

	return 0;
}

Compilation message (stderr)

bridges.cpp: In lambda function:
bridges.cpp:89:34: error: no match for 'operator<<' (operand types are 'std::basic_ostream<char>' and 'std::pair<int, int>')
   89 |     cerr << "QUERY " << b << ' ' << mp(a, d) << '\n';
      |                                  ^~
In file included from /usr/include/c++/10/istream:39,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/ostream:108:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__ostream_type& (*)(std::basic_ostream<_CharT, _Traits>::__ostream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  108 |       operator<<(__ostream_type& (*__pf)(__ostream_type&))
      |       ^~~~~~~~
/usr/include/c++/10/ostream:108:36: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'std::basic_ostream<char>::__ostream_type& (*)(std::basic_ostream<char>::__ostream_type&)' {aka 'std::basic_ostream<char>& (*)(std::basic_ostream<char>&)'}
  108 |       operator<<(__ostream_type& (*__pf)(__ostream_type&))
      |                  ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/ostream:117:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__ios_type& (*)(std::basic_ostream<_CharT, _Traits>::__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>; std::basic_ostream<_CharT, _Traits>::__ios_type = std::basic_ios<char>]'
  117 |       operator<<(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/10/ostream:117:32: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'std::basic_ostream<char>::__ios_type& (*)(std::basic_ostream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'}
  117 |       operator<<(__ios_type& (*__pf)(__ios_type&))
      |                  ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
/usr/include/c++/10/ostream:127:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  127 |       operator<<(ios_base& (*__pf) (ios_base&))
      |       ^~~~~~~~
/usr/include/c++/10/ostream:127:30: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'std::ios_base& (*)(std::ios_base&)'
  127 |       operator<<(ios_base& (*__pf) (ios_base&))
      |                  ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
/usr/include/c++/10/ostream:166:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  166 |       operator<<(long __n)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:166:23: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'long int'
  166 |       operator<<(long __n)
      |                  ~~~~~^~~
/usr/include/c++/10/ostream:170:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  170 |       operator<<(unsigned long __n)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:170:32: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'long unsigned int'
  170 |       operator<<(unsigned long __n)
      |                  ~~~~~~~~~~~~~~^~~
/usr/include/c++/10/ostream:174:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(bool) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  174 |       operator<<(bool __n)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:174:23: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'bool'
  174 |       operator<<(bool __n)
      |                  ~~~~~^~~
In file included from /usr/include/c++/10/ostream:784,
                 from /usr/include/c++/10/istream:39,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/bits/ostream.tcc:91:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short int) [with _CharT = char; _Traits = std::char_traits<char>]'
   91 |     basic_ostream<_CharT, _Traits>::
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/bits/ostream.tcc:92:22: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'short int'
   92 |     operator<<(short __n)
      |                ~~~~~~^~~
In file included from /usr/include/c++/10/istream:39,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/ostream:181:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(short unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  181 |       operator<<(unsigned short __n)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:181:33: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'short unsigned int'
  181 |       operator<<(unsigned short __n)
      |                  ~~~~~~~~~~~~~~~^~~
In file included from /usr/include/c++/10/ostream:784,
                 from /usr/include/c++/10/istream:39,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/bits/ostream.tcc:105:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(int) [with _CharT = char; _Traits = std::char_traits<char>]'
  105 |     basic_ostream<_CharT, _Traits>::
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/bits/ostream.tcc:106:20: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'int'
  106 |     operator<<(int __n)
      |                ~~~~^~~
In file included from /usr/include/c++/10/istream:39,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/ostream:192:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  192 |       operator<<(unsigned int __n)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:192:31: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'unsigned int'
  192 |       operator<<(unsigned int __n)
      |                  ~~~~~~~~~~~~~^~~
/usr/include/c++/10/ostream:201:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  201 |       operator<<(long long __n)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:201:28: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'long long int'
  201 |       operator<<(long long __n)
      |                  ~~~~~~~~~~^~~
/usr/include/c++/10/ostream:205:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  205 |       operator<<(unsigned long long __n)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:205:37: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'long long unsigned int'
  205 |       operator<<(unsigned long long __n)
      |                  ~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/10/ostream:220:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(double) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  220 |       operator<<(double __f)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:220:25: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'double'
  220 |       operator<<(double __f)
      |                  ~~~~~~~^~~
/usr/include/c++/10/ostream:224:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(float) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  224 |       operator<<(float __f)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:224:24: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'float'
  224 |       operator<<(float __f)
      |                  ~~~~~~^~~
/usr/include/c++/10/ostream:232:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long double) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  232 |       operator<<(long double __f)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:232:30: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'long double'
  232 |       operator<<(long double __f)
      |                  ~~~~~~~~~~~~^~~
/usr/include/c++/10/ostream:245:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(const void*) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
  245 |       operator<<(const void* __p)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:245:30: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'const void*'
  245 |       operator<<(const void* __p)
      |                  ~~~~~~~~~~~~^~~
/usr/include/c++/10/ostream:250:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::nullptr_t) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>; std::nullptr_t = std::nullptr_t]'
  250 |       operator<<(nullptr_t)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:250:18: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'std::nullptr_t'
  250 |       operator<<(nullptr_t)
      |                  ^~~~~~~~~
In file included from /usr/include/c++/10/ostream:784,
                 from /usr/include/c++/10/istream:39,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/bits/ostream.tcc:119:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__streambuf_type*) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__streambuf_type = std::basic_streambuf<char>]'
  119 |     basic_ostream<_CharT, _Traits>::
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/bits/ostream.tcc:120:34: note:   no known conversion for argument 1 from 'std::pair<int, int>' to 'std::basic_ostream<char>::__streambuf_type*' {aka 'std::basic_streambuf<char>*'}
  120 |     operator<<(__streambuf_type* __sbin)
      |                ~~~~~~~~~~~~~~~~~~^~~~~~
In file included from /usr/include/c++/10/regex:62,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:110,
                 from bridges.cpp:1:
/usr/include/c++/10/bits/regex.h:1647:5: note: candidate: 'template<class _Ch_type, class _Ch_traits, class _Bi_iter> std::basic_ostream<_CharT, _Traits>& std::__cxx11::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::__cxx11::sub_match<_Bi_iter>&)'
 1647 |     operator<<(basic_ostream<_Ch_type, _Ch_traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/10/bits/regex.h:1647:5: note:   template argument deduction/substitution failed:
bridges.cpp:89:44: note:   'std::pair<int, int>' is not derived from 'const std::__cxx11::sub_match<_Bi_iter>'
   89 |     cerr << "QUERY " << b << ' ' << mp(a, d) << '\n';
      |                                            ^
In file included from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:45,
                 from bridges.cpp:1:
/usr/include/c++/10/cstddef:125:5: note: candidate: 'template<class _IntegerType> constexpr std::__byte_op_t<_IntegerType> std::operator<<(std::byte, _IntegerType)'
  125 |     operator<<(byte __b, _IntegerType __shift) noexcept
      |     ^~~~~~~~
/usr/include/c++/10/cstddef:125:5: note:   template argument deduction/substitution failed:
bridges.cpp:89:27: note:   cannot convert 'std::operator<< <std::char_traits<char> >((* &(& std::operator<< <std::char_traits<char> >(std::cout, ((const char*)"QUERY ")))->std::basic_ostream<char>::operator<<(b)), 32)' (type 'std::basic_ostream<char>') to type 'std::byte'
   89 |     cerr << "QUERY " << b << ' ' << mp(a, d) << '\n';
      |                           ^
In file included from /usr/include/c++/10/bits/basic_string.h:48,
                 from /usr/include/c++/10/string:55,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/string_view:622:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::basic_string_view<_CharT, _Traits>)'
  622 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/10/string_view:622:5: note:   template argument deduction/substitution failed:
bridges.cpp:89:44: note:   'std::pair<int, int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   89 |     cerr << "QUERY " << b << ' ' << mp(a, d) << '\n';
      |                                            ^
In file included from /usr/include/c++/10/string:55,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/bits/basic_string.h:6458:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 6458 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/10/bits/basic_string.h:6458:5: note:   template argument deduction/substitution failed:
bridges.cpp:89:44: note:   'std::pair<int, int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   89 |     cerr << "QUERY " << b << ' ' << mp(a, d) << '\n';
      |                                            ^
In file included from /usr/include/c++/10/bits/ios_base.h:46,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/system_error:262:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::error_code&)'
  262 |     operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
      |     ^~~~~~~~
/usr/include/c++/10/system_error:262:5: note:   template argument deduction/substitution failed:
bridges.cpp:89:39: note:   cannot convert 'std::make_pair<int&, int&>((* & a), (* & d))' (type 'std::pair<int, int>') to type 'const std::error_code&'
   89 |     cerr << "QUERY " << b << ' ' << mp(a, d) << '\n';
      |                                       ^
In file included from /usr/include/c++/10/istream:39,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from bridges.cpp:1:
/usr/include/c++/10/ostream:506:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, _CharT)'
  506 |     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
      |     ^~~~~~~~
/usr/include/c++/10/ostream:506:5: note:   te