Submission #1011443

# Submission time Handle Problem Language Result Execution time Memory
1011443 2024-06-30T13:48:08 Z Double_Slash Languages (IOI10_languages) C++17
Compilation error
0 ms 0 KB
#include "lang.h"
#include "grader.h"
#include <bits/stdc++.h>
 
using namespace std;
#define debug(x) [&] { auto _x = x; cerr << __LINE__ << ": " << #x << " = " << _x << endl; return _x; }()
using ll = long long;
using pint = pair<int, int>;
 
double magic(double x) {
	return abs(x);
}

template <typename T, class Hash, int MAX>
struct Data {
	int tot = 0;
    unordered_map<T, int, Hash> m;
  set<pair<int, T>> inv;
 
	double operator&(const Data<T, Hash, MAX> &o) const {
		double ret = 0;
		for (auto [k, v]: m) {
			ret += magic((double) v / tot - (o.m.count(k) ? (double) o.m.at(k) / o.tot : 0));
		}
		for (auto [k, v]: o.m) {
			if (not m.contains(k)) ret += magic((double) v / o.tot);
		}
		return ret;
	}
 
	void operator+=(const Data<T, Hash, MAX> &o) {
		for (auto &[k, v]: o.) {
          inv.erase({m[k], k});
			inv.emplace(m[k] += v, k);
		}
		tot += o.tot;
      while (inv.size() > MAX) {
          tot -= inv.begin()->first;
          m.erase(inv.begin()->second);
        inv.erase(inv.begin());
}
	}};

struct hash2 {
ll operator() (const pint &x) { return (ll) x.first << 16 | x.second; }
};
struct hash3 {
ll operator()(const array<int, 3> &x) { return ((ll) x[0] << 32) | ((ll) x[1] << 16) | x[2]; }
};
 
struct Profile {
Data<int, hash<int>, 50> sing;
  Data<pint, hash2, 50> doub;
  Data<array<int, 3>, hash3, 50> trip;
 
	Profile() {}
 
	Profile(int *arr) {
		for (int i = 0; i < 100; ++i) {
          sing.m[arr[i]]++;
          if (i) doub.m[{arr[i - 1], arr[i]}]++;
          if (i >=2) trip.m[{arr[i - 2], arr[i - 1], arr[i]}];
		}
      for (auto [k, v]: sing.m) sing.inv.emplace(v, k);
      for (auto [k, v]: doub.m) doub.inv.emplace(v, k);
            for (auto [k, v]: trip.m) trip.inv.emplace(v, k);
      
      sing.tot = 100;
      doub.tot = 99;
      trip.tot = 98;
	}
 
	double operator&(const Profile &o) const {
		return (sing & o.sing) + (doub & o.doub) + (trip & o.trip);
	}
 
	void operator+=(const Profile &o) {
      sing += o.sing;
doub += o.doub;
      trip += o.trip;
	}
} profile[56];
 
void excerpt(int *E) {
	Profile p(E);
	pair<double, int> mn{1e18, 0};
	for (int i = 0; i < 56; ++i) {
		mn = min(mn, {p & profile[i], i});
	}
	int ans = language(mn.second);
	profile[ans] += p;
}

Compilation message

lang.cpp: In member function 'void Data<T, Hash, MAX>::operator+=(const Data<T, Hash, MAX>&)':
lang.cpp:32:24: error: expected unqualified-id before ')' token
   32 |   for (auto &[k, v]: o.) {
      |                        ^
lang.cpp: In instantiation of 'double Data<T, Hash, MAX>::operator&(const Data<T, Hash, MAX>&) const [with T = int; Hash = std::hash<int>; int MAX = 50]':
lang.cpp:74:20:   required from here
lang.cpp:26:14: error: 'const class std::unordered_map<int, int>' has no member named 'contains'
   26 |    if (not m.contains(k)) ret += magic((double) v / o.tot);
      |            ~~^~~~~~~~
lang.cpp: In instantiation of 'double Data<T, Hash, MAX>::operator&(const Data<T, Hash, MAX>&) const [with T = std::pair<int, int>; Hash = hash2; int MAX = 50]':
lang.cpp:74:38:   required from here
lang.cpp:26:14: error: 'const class std::unordered_map<std::pair<int, int>, int, hash2, std::equal_to<std::pair<int, int> >, std::allocator<std::pair<const std::pair<int, int>, int> > >' has no member named 'contains'
lang.cpp: In instantiation of 'double Data<T, Hash, MAX>::operator&(const Data<T, Hash, MAX>&) const [with T = std::array<int, 3>; Hash = hash3; int MAX = 50]':
lang.cpp:74:56:   required from here
lang.cpp:26:14: error: 'const class std::unordered_map<std::array<int, 3>, int, hash3, std::equal_to<std::array<int, 3> >, std::allocator<std::pair<const std::array<int, 3>, int> > >' has no member named 'contains'
lang.cpp: In instantiation of 'void Data<T, Hash, MAX>::operator+=(const Data<T, Hash, MAX>&) [with T = int; Hash = std::hash<int>; int MAX = 50]':
lang.cpp:78:17:   required from here
lang.cpp:33:24: error: use of 'k' before deduction of 'auto'
   33 |           inv.erase({m[k], k});
      |                        ^
lang.cpp:33:20: error: no matching function for call to 'std::set<std::pair<int, int>, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::erase(<brace-enclosed initializer list>)'
   33 |           inv.erase({m[k], k});
      |           ~~~~~~~~~^~~~~~~~~~~
In file included from /usr/include/c++/10/set:61,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:87,
                 from lang.cpp:3:
/usr/include/c++/10/bits/stl_set.h:654:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::erase(std::set<_Key, _Compare, _Alloc>::const_iterator) [with _Key = std::pair<int, int>; _Compare = std::less<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >; std::set<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator; std::set<_Key, _Compare, _Alloc>::const_iterator = std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator]'
  654 |       erase(const_iterator __position)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:654:28: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'std::set<std::pair<int, int>, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'}
  654 |       erase(const_iterator __position)
      |             ~~~~~~~~~~~~~~~^~~~~~~~~~
/usr/include/c++/10/bits/stl_set.h:684:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::size_type std::set<_Key, _Compare, _Alloc>::erase(const key_type&) [with _Key = std::pair<int, int>; _Compare = std::less<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >; std::set<_Key, _Compare, _Alloc>::size_type = long unsigned int; std::set<_Key, _Compare, _Alloc>::key_type = std::pair<int, int>]'
  684 |       erase(const key_type& __x)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:684:29: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const key_type&' {aka 'const std::pair<int, int>&'}
  684 |       erase(const key_type& __x)
      |             ~~~~~~~~~~~~~~~~^~~
/usr/include/c++/10/bits/stl_set.h:706:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::erase(std::set<_Key, _Compare, _Alloc>::const_iterator, std::set<_Key, _Compare, _Alloc>::const_iterator) [with _Key = std::pair<int, int>; _Compare = std::less<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >; std::set<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator; std::set<_Key, _Compare, _Alloc>::const_iterator = std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator]'
  706 |       erase(const_iterator __first, const_iterator __last)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:706:7: note:   candidate expects 2 arguments, 1 provided
lang.cpp:34:24: error: use of 'v' before deduction of 'auto'
   34 |    inv.emplace(m[k] += v, k);
      |                        ^
lang.cpp: In instantiation of 'void Data<T, Hash, MAX>::operator+=(const Data<T, Hash, MAX>&) [with T = std::pair<int, int>; Hash = hash2; int MAX = 50]':
lang.cpp:79:11:   required from here
lang.cpp:33:24: error: use of 'k' before deduction of 'auto'
   33 |           inv.erase({m[k], k});
      |                        ^
lang.cpp:33:20: error: no matching function for call to 'std::set<std::pair<int, std::pair<int, int> >, std::less<std::pair<int, std::pair<int, int> > >, std::allocator<std::pair<int, std::pair<int, int> > > >::erase(<brace-enclosed initializer list>)'
   33 |           inv.erase({m[k], k});
      |           ~~~~~~~~~^~~~~~~~~~~
In file included from /usr/include/c++/10/set:61,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:87,
                 from lang.cpp:3:
/usr/include/c++/10/bits/stl_set.h:654:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::erase(std::set<_Key, _Compare, _Alloc>::const_iterator) [with _Key = std::pair<int, std::pair<int, int> >; _Compare = std::less<std::pair<int, std::pair<int, int> > >; _Alloc = std::allocator<std::pair<int, std::pair<int, int> > >; std::set<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree<std::pair<int, std::pair<int, int> >, std::pair<int, std::pair<int, int> >, std::_Identity<std::pair<int, std::pair<int, int> > >, std::less<std::pair<int, std::pair<int, int> > >, std::allocator<std::pair<int, std::pair<int, int> > > >::const_iterator; std::set<_Key, _Compare, _Alloc>::const_iterator = std::_Rb_tree<std::pair<int, std::pair<int, int> >, std::pair<int, std::pair<int, int> >, std::_Identity<std::pair<int, std::pair<int, int> > >, std::less<std::pair<int, std::pair<int, int> > >, std::allocator<std::pair<int, std::pair<int, int> > > >::const_iterator]'
  654 |       erase(const_iterator __position)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:654:28: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'std::set<std::pair<int, std::pair<int, int> >, std::less<std::pair<int, std::pair<int, int> > >, std::allocator<std::pair<int, std::pair<int, int> > > >::const_iterator' {aka 'std::_Rb_tree<std::pair<int, std::pair<int, int> >, std::pair<int, std::pair<int, int> >, std::_Identity<std::pair<int, std::pair<int, int> > >, std::less<std::pair<int, std::pair<int, int> > >, std::allocator<std::pair<int, std::pair<int, int> > > >::const_iterator'}
  654 |       erase(const_iterator __position)
      |             ~~~~~~~~~~~~~~~^~~~~~~~~~
/usr/include/c++/10/bits/stl_set.h:684:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::size_type std::set<_Key, _Compare, _Alloc>::erase(const key_type&) [with _Key = std::pair<int, std::pair<int, int> >; _Compare = std::less<std::pair<int, std::pair<int, int> > >; _Alloc = std::allocator<std::pair<int, std::pair<int, int> > >; std::set<_Key, _Compare, _Alloc>::size_type = long unsigned int; std::set<_Key, _Compare, _Alloc>::key_type = std::pair<int, std::pair<int, int> >]'
  684 |       erase(const key_type& __x)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:684:29: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const key_type&' {aka 'const std::pair<int, std::pair<int, int> >&'}
  684 |       erase(const key_type& __x)
      |             ~~~~~~~~~~~~~~~~^~~
/usr/include/c++/10/bits/stl_set.h:706:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::erase(std::set<_Key, _Compare, _Alloc>::const_iterator, std::set<_Key, _Compare, _Alloc>::const_iterator) [with _Key = std::pair<int, std::pair<int, int> >; _Compare = std::less<std::pair<int, std::pair<int, int> > >; _Alloc = std::allocator<std::pair<int, std::pair<int, int> > >; std::set<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree<std::pair<int, std::pair<int, int> >, std::pair<int, std::pair<int, int> >, std::_Identity<std::pair<int, std::pair<int, int> > >, std::less<std::pair<int, std::pair<int, int> > >, std::allocator<std::pair<int, std::pair<int, int> > > >::const_iterator; std::set<_Key, _Compare, _Alloc>::const_iterator = std::_Rb_tree<std::pair<int, std::pair<int, int> >, std::pair<int, std::pair<int, int> >, std::_Identity<std::pair<int, std::pair<int, int> > >, std::less<std::pair<int, std::pair<int, int> > >, std::allocator<std::pair<int, std::pair<int, int> > > >::const_iterator]'
  706 |       erase(const_iterator __first, const_iterator __last)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:706:7: note:   candidate expects 2 arguments, 1 provided
lang.cpp:34:24: error: use of 'v' before deduction of 'auto'
   34 |    inv.emplace(m[k] += v, k);
      |                        ^
lang.cpp: In instantiation of 'void Data<T, Hash, MAX>::operator+=(const Data<T, Hash, MAX>&) [with T = std::array<int, 3>; Hash = hash3; int MAX = 50]':
lang.cpp:80:17:   required from here
lang.cpp:33:24: error: use of 'k' before deduction of 'auto'
   33 |           inv.erase({m[k], k});
      |                        ^
lang.cpp:33:20: error: no matching function for call to 'std::set<std::pair<int, std::array<int, 3> >, std::less<std::pair<int, std::array<int, 3> > >, std::allocator<std::pair<int, std::array<int, 3> > > >::erase(<brace-enclosed initializer list>)'
   33 |           inv.erase({m[k], k});
      |           ~~~~~~~~~^~~~~~~~~~~
In file included from /usr/include/c++/10/set:61,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:87,
                 from lang.cpp:3:
/usr/include/c++/10/bits/stl_set.h:654:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::erase(std::set<_Key, _Compare, _Alloc>::const_iterator) [with _Key = std::pair<int, std::array<int, 3> >; _Compare = std::less<std::pair<int, std::array<int, 3> > >; _Alloc = std::allocator<std::pair<int, std::array<int, 3> > >; std::set<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree<std::pair<int, std::array<int, 3> >, std::pair<int, std::array<int, 3> >, std::_Identity<std::pair<int, std::array<int, 3> > >, std::less<std::pair<int, std::array<int, 3> > >, std::allocator<std::pair<int, std::array<int, 3> > > >::const_iterator; std::set<_Key, _Compare, _Alloc>::const_iterator = std::_Rb_tree<std::pair<int, std::array<int, 3> >, std::pair<int, std::array<int, 3> >, std::_Identity<std::pair<int, std::array<int, 3> > >, std::less<std::pair<int, std::array<int, 3> > >, std::allocator<std::pair<int, std::array<int, 3> > > >::const_iterator]'
  654 |       erase(const_iterator __position)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:654:28: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'std::set<std::pair<int, std::array<int, 3> >, std::less<std::pair<int, std::array<int, 3> > >, std::allocator<std::pair<int, std::array<int, 3> > > >::const_iterator' {aka 'std::_Rb_tree<std::pair<int, std::array<int, 3> >, std::pair<int, std::array<int, 3> >, std::_Identity<std::pair<int, std::array<int, 3> > >, std::less<std::pair<int, std::array<int, 3> > >, std::allocator<std::pair<int, std::array<int, 3> > > >::const_iterator'}
  654 |       erase(const_iterator __position)
      |             ~~~~~~~~~~~~~~~^~~~~~~~~~
/usr/include/c++/10/bits/stl_set.h:684:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::size_type std::set<_Key, _Compare, _Alloc>::erase(const key_type&) [with _Key = std::pair<int, std::array<int, 3> >; _Compare = std::less<std::pair<int, std::array<int, 3> > >; _Alloc = std::allocator<std::pair<int, std::array<int, 3> > >; std::set<_Key, _Compare, _Alloc>::size_type = long unsigned int; std::set<_Key, _Compare, _Alloc>::key_type = std::pair<int, std::array<int, 3> >]'
  684 |       erase(const key_type& __x)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:684:29: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const key_type&' {aka 'const std::pair<int, std::array<int, 3> >&'}
  684 |       erase(const key_type& __x)
      |             ~~~~~~~~~~~~~~~~^~~
/usr/include/c++/10/bits/stl_set.h:706:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::erase(std::set<_Key, _Compare, _Alloc>::const_iterator, std::set<_Key, _Compare, _Alloc>::const_iterator) [with _Key = std::pair<int, std::array<int, 3> >; _Compare = std::less<std::pair<int, std::array<int, 3> > >; _Alloc = std::allocator<std::pair<int, std::array<int, 3> > >; std::set<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree<std::pair<int, std::array<int, 3> >, std::pair<int, std::array<int, 3> >, std::_Identity<std::pair<int, std::array<int, 3> > >, std::less<std::pair<int, std::array<int, 3> > >, std::allocator<std::pair<int, std::array<int, 3> > > >::const_iterator; std::set<_Key, _Compare, _Alloc>::const_iterator = std::_Rb_tree<std::pair<int, std::array<int, 3> >, std::pair<int, std::array<int, 3> >, std::_Identity<std::pair<int, std::array<int, 3> > >, std::less<std::pair<int, std::array<int, 3> > >, std::allocator<std::pair<int, std::array<int, 3> > > >::const_iterator]'
  706 |       erase(const_iterator __first, const_iterator __last)
      |       ^~~~~
/usr/include/c++/10/bits/stl_set.h:706:7: note:   candidate expects 2 arguments, 1 provided
lang.cpp:34:24: error: use of 'v' before deduction of 'auto'
   34 |    inv.emplace(m[k] += v, k);
      |                        ^
In file included from /usr/include/c++/10/bits/hashtable.h:35,
                 from /usr/include/c++/10/unordered_map:46,
                 from /usr/include/c++/10/functional:61,
                 from /usr/include/c++/10/pstl/glue_algorithm_defs.h:13,
                 from /usr/include/c++/10/algorithm:74,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:65,
                 from lang.cpp:3:
/usr/include/c++/10/bits/hashtable_policy.h: In instantiation of 'std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, std::__detail::_Default_ranged_hash, true>::__hash_code std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, std::__detail::_Default_ranged_hash, true>::_M_hash_code(const _Key&) const [with _Key = std::pair<int, int>; _Value = std::pair<const std::pair<int, int>, int>; _ExtractKey = std::__detail::_Select1st; _H1 = hash2; _H2 = std::__detail::_Mod_range_hashing; std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, std::__detail::_Default_ranged_hash, true>::__hash_code = long unsigned int]':
/usr/include/c++/10/bits/hashtable_policy.h:734:45:   required from 'std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::mapped_type& std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::operator[](std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::key_type&&) [with _Key = std::pair<int, int>; _Pair = std::pair<const std::pair<int, int>, int>; _Alloc = std::allocator<std::pair<const std::pair<int, int>, int> >; _Equal = std::equal_to<std::pair<int, int> >; _H1 = hash2; _H2 = std::__detail::_Mod_range_hashing; _Hash = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, false, true>; std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::mapped_type = int; std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::key_type = std::pair<int, int>]'
/usr/include/c++/10/bits/unordered_map.h:988:20:   required from 'std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::mapped_type& std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::key_type&&) [with _Key = std::pair<int, int>; _Tp = int; _Hash = hash2; _Pred = std::equal_to<std::pair<int, int> >; _Alloc = std::allocator<std::pair<const std::pair<int, int>, int> >; std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::mapped_type = int; std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::key_type = std::pair<int, int>]'
lang.cpp:61:45:   required from here
/usr/include/c++/10/bits/hashtable_policy.h:1377:16: error: static assertion failed: hash function must be invocable with an argument of key type
 1377 |  static_assert(__is_invocable<const _H1&, const _Key&>{},
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/bits/hashtable_policy.h:1379:16: error: no match for call to '(const hash2) (const std::pair<int, int>&)'
 1379 |  return _M_h1()(__k);
      |         ~~~~~~~^~~~~
lang.cpp:45:4: note: candidate: 'll hash2::operator()(const pint&)' (near match)
   45 | ll operator() (const pint &x) { return (ll) x.first << 16 | x.second; }
      |    ^~~~~~~~
lang.cpp:45:4: note:   passing 'const hash2*' as 'this' argument discards qualifiers
In file included from /usr/include/c++/10/bits/hashtable.h:35,
                 from /usr/include/c++/10/unordered_map:46,
                 from /usr/include/c++/10/functional:61,
                 from /usr/include/c++/10/pstl/glue_algorithm_defs.h:13,
                 from /usr/include/c++/10/algorithm:74,
                 from /usr/include/x86_64-linux-gnu/c+