Submission #1025960

# Submission time Handle Problem Language Result Execution time Memory
1025960 2024-07-17T11:52:51 Z toan2602 Factories (JOI14_factories) C++14
Compilation error
0 ms 0 KB
#include<bits/stdc++.h>
#include "factories.h"

using namespace std;
#define int long long
int n, a[500005], b[500005], d[500005], tin[500005], tout[500005], timer = -1, s, t, x[500005], y[500005], q, w[500005], dp[2][500005], col[500005];
vector<pair<int,int>> adj[500005], adj2[500005];
pair<int, int> up[20][500005];
vector<int> euler;
int res = 1e18;
bool cmp(int a, int b) {
	return tin[a] < tin[b];
}
void dfs(int u, int par) {
	tin[u] = ++timer;
	euler.push_back(u);
	for (pair<int, int> node: adj[u]) {
		if(node.first == par) continue;
		w[node.first] = w[u] + node.second;
		dfs(node.first, u);
		timer++;
		euler.push_back(u);
	}
	tout[u] = timer;
}
void build() {
	for (int i = 0; i < euler.size(); i++) up[0][i] = {tin[euler[i]], euler[i]};
	for (int i = 1; i < 20; i++) {
		for (int j = 0; j + (1<<i) - 1 < euler.size(); j++) {
			up[i][j] = min(up[i-1][j], up[i-1][j+(1<<(i-1))]);
		}
	}
}
pair<int, int> get(int u, int v) {
	int lg = __lg(v - u + 1);
	return min(up[lg][u], up[lg][v-(1<<lg)+1]);
}
void dfs2(int u, int par) {
	dp[0][u] = dp[1][u] = 1e18;
	for (pair<int, int> node: adj2[u]) {
		if(node.first == par) continue;
		dfs2(node.first, u);
		dp[0][u] = min(dp[0][u], dp[0][node.first] + node.second);
		dp[1][u] = min(dp[1][u], dp[1][node.first] + node.second);
		if(col[node.first] == 1) dp[0][u] = min(dp[0][u], w[node.first] - w[u]);
		if(col[node.first] == 2) dp[1][u] = min(dp[1][u], w[node.first] - w[u]);
	}
	if(col[u] == 1) res = min(res, dp[1][u]);
	if(col[u] == 2) res = min(res, dp[0][u]);
	res = min(res, dp[1][u] + dp[0][u]);
}
long long Query(int s, int x[], int t, int y[]) {
	vector<int> v, v2;
	int root, mx = 1e18;
	for (int i = 1; i <= s; i++) {x[i]++, col[x[i]] = 1, v.push_back(x[i]); if(mx > tin[x[i]]) mx = tin[x[i]], root = x[i];}
	for (int i = 1; i <= t; i++) {y[i]++, col[y[i]] = 2, v.push_back(y[i]); if(mx > tin[y[i]]) mx = tin[y[i]], root = y[i];}
	sort(v.begin(), v.end(), cmp);
	v2 = v;
	for (int i = 0; i < v.size() - 1; i++) {
		pair<int, int> lca = get(tin[v[i]], tin[v[i+1]]);
		v2.push_back(lca.second);
		if(mx > lca.first) mx = lca.first, root = lca.second;
	}
	sort(v2.begin(), v2.end(), cmp);
	stack<int> S;
	S.push(v2[0]);
	for (int i = 1; i < v2.size(); i++) {
		int cur = S.top(), p = v2[i];
		if(tin[p] == tin[cur]) continue;
		while(tin[cur] > tin[p] || tout[cur] < tin[p]) {
			S.pop();
			cur = S.top();
		}
		adj2[cur].push_back({p, w[p] - w[cur]});
		S.push(p);
	}
	res = 1e18;
	dfs2(root, -1);
	for (int i = 1; i <= s; i++) col[x[i]] = 0;
	for (int i = 1; i <= t; i++) col[y[i]] = 0;
	return res;
}
void init(int n, int a[], int b[], int d[]) {
	cin >> q;
	for (int i = 1; i < n; i++) {
		a[i]++, b[i]++;
		adj[a[i]].push_back({b[i], d[i]});
		adj[b[i]].push_back({a[i], d[i]});
	}
	dfs(1, -1);
	build();
	while(q--) {
		cout << Query << '\n';
	}
}

Compilation message

factories.cpp: In function 'void build()':
factories.cpp:27:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |  for (int i = 0; i < euler.size(); i++) up[0][i] = {tin[euler[i]], euler[i]};
      |                  ~~^~~~~~~~~~~~~~
factories.cpp:29:34: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |   for (int j = 0; j + (1<<i) - 1 < euler.size(); j++) {
      |                   ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
factories.cpp: In function 'long long int Query(long long int, long long int*, long long int, long long int*)':
factories.cpp:59:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |  for (int i = 0; i < v.size() - 1; i++) {
      |                  ~~^~~~~~~~~~~~~~
factories.cpp:67:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |  for (int i = 1; i < v2.size(); i++) {
      |                  ~~^~~~~~~~~~~
factories.cpp: In function 'void init(long long int, long long int*, long long int*, long long int*)':
factories.cpp:93:8: error: no match for 'operator<<' (operand types are 'std::ostream' {aka 'std::basic_ostream<char>'} and '<unresolved overloaded function type>')
   93 |   cout << Query << '\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 factories.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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 factories.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 '<unresolved overloaded function type>' 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 factories.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 '<unresolved overloaded function type>' 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 factories.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 '<unresolved overloaded function type>' 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 factories.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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' 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 '<unresolved overloaded function type>' to 'const void*'
  245 |       operator<<(const void* __p)
      |                  ~~~~~~~~~~~~^~~
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 factories.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 '<unresolved overloaded function type>' 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 factories.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:
factories.cpp:93:11: note:   mismatched types 'const std::__cxx11::sub_match<_Bi_iter>' and 'long long int(long long int, long long int*, long long int, long long int*)'
   93 |   cout << Query << '\n';
      |           ^~~~~
factories.cpp:93:11: note:   mismatched types 'const std::__cxx11::sub_match<_Bi_iter>' and 'long long int(int, int*, int, int*)'
factories.cpp:93:11: note:   couldn't deduce template parameter '_Bi_iter'
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 factories.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, _Alloc>&)'
 6458 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/10/bits/basic_string.h:6458:5: note:   template argument deduction/substitution failed:
factories.cpp:93:11: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>' and 'long long int(long long int, long long int*, long long int, long long int*)'
   93 |   cout << Query << '\n';
      |           ^~~~~
factories.cpp:93:11: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>' and 'long long int(int, int*, int, int*)'
factories.cpp:93:11: note:   couldn't deduce template parameter '_Alloc'
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 factories.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:
factories.cpp:93:11: note:   cannot convert 'Query' (type '<unresolved overloaded function type>') to type 'const std::error_code&'
   93 |   cout << Query << '\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 factories.cpp:1:
/usr/include/c++/10/ostream:506:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, _CharT) [with _CharT = char; _Traits = std::char_traits<char>]'
  506 |     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
      |     ^~~~~~~~
/usr/include/c++/10/ostream:506:62: note:   no known conversion for argument 2 from '<unresolved overloaded function type>' to 'char'
  506 |     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
      |                                                       ~~~~~~~^~~
/usr/include/c++/10/ostream:511:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, char)'
  511 |     operator<<(basic_ostre