Language: C++

#define _USE_MATH_DEFINES
#include<bits/stdc++.h>
using namespace std;
using ll = long long;


struct State {
	int cur, prev, carrot;
	double d;
	State(int cur_, int prev_, int carrot_, double d_) {
		cur = cur_;
		prev = prev_;
		carrot = carrot_;
		d = d_;
	}
	bool operator<(const State& right) const {
		return d > right.d;
	}
};

int x[22], y[22];
double r, theta;

bool check_angle(int p, int i, int n) {
	double a1 = x[i] - x[p], a2 = y[i] - y[p];
	double b1 = x[n] - x[i], b2 = y[n] - y[i];
	double cos_theta = (a1 * b1 + a2 * b2) / (sqrt(a1 * a1 + a2 * a2) * sqrt(b1 * b1 + b2 * b2));
	return cos_theta > cos(theta * M_PI / 180);
}

tuple<int, int, int> to_key(const State& s) {
	return make_tuple(s.cur, s.prev, s.carrot);
}

int main() {
	int n;
	cin >> n;
	cin >> r >> theta;

	for(int i=0;i<n;i++) {
		cin >> x[i] >> y[i];
	}

	priority_queue<State> que;
	que.emplace(0, n, 0, 0);

	unordered_map<tuple<int, int, int>, double> memo;
	memo[to_key(que.top())] = 0;

	int ans = 0;
	while(!que.empty()) {
		State s = que.top();
		que.pop();
		auto key = to_key(s);
		if (memo[key] < s.d) continue;
		ans = max(ans, s.carrot);

		for(int to=0;to<n;to++) {
			if (to == s.cur) continue;
			if (s.prev != n && !check_angle(s.prev, s.cur, to)) continue;
			double nd = s.d + sqrt((x[s.cur] - x[to]) * (x[s.cur] - x[to]) + (y[s.cur] - y[to]) * (y[s.cur] - y[to]));
			if (nd > r) continue;

			auto next_key = make_tuple(to, s.cur, s.carrot + 1);
			if (memo.find(next_key) == memo.end() || memo[next_key] > nd) {
				memo[next_key] = nd;
				que.emplace(to, s.cur, s.carrot + 1, nd);
			}
		}
	}
	cout << ans << endl;

	return 0;
}



Compiler output:
a.cc: In function 'int main()':
a.cc:47:53: error: use of deleted function 'std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map() [with _Key = std::tuple<int, int, int>; _Tp = double; _Hash = std::hash<std::tuple<int, int, int> >; _Pred = std::equal_to<std::tuple<int, int, int> >; _Alloc = std::allocator<std::pair<const std::tuple<int, int, int>, double> >]'
   47 |         unordered_map<tuple<int, int, int>, double> memo;
      |                                                     ^~~~
In file included from /usr/include/c++/14/unordered_map:41,
                 from /usr/include/c++/14/functional:63,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53,
                 from a.cc:2:
/usr/include/c++/14/bits/unordered_map.h:148:7: note: 'std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map() [with _Key = std::tuple<int, int, int>; _Tp = double; _Hash = std::hash<std::tuple<int, int, int> >; _Pred = std::equal_to<std::tuple<int, int, int> >; _Alloc = std::allocator<std::pair<const std::tuple<int, int, int>, double> >]' is implicitly deleted because the default definition would be ill-formed:
  148 |       unordered_map() = default;
      |       ^~~~~~~~~~~~~
/usr/include/c++/14/bits/unordered_map.h: At global scope:
/usr/include/c++/14/bits/unordered_map.h:148:7: error: use of deleted function 'std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::_Hashtable() [with _Key = std::tuple<int, int, int>; _Value = std::pair<const std::tuple<int, int, int>, double>; _Alloc = std::allocator<std::pair<const std::tuple<int, int, int>, double> >; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<std::tuple<int, int, int> >; _Hash = std::hash<std::tuple<int, int, int> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, false, true>]'
In file included from /usr/include/c++/14/bits/unordered_map.h:33:
/usr/include/c++/14/bits/hashtable.h:539:7: note: 'std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::_Hashtable() [with _Key = std::tuple<int, int, int>; _Value = std::pair<const std::tuple<int, int, int>, double>; _Alloc = std::allocator<std::pair<const std::tuple<int, int, int>, double> >; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<std::tuple<int, int, int> >; _Hash = std::hash<std::tuple<int, int, int> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, false, true>]' is implicitly deleted because the default definition would be ill-formed:
  539 |       _Hashtable() = default;
      |       ^~~~~~~~~~
/usr/include/c++/14/bits/hashtable.h:539:7: error: use of deleted function 'std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _Traits>::_Hashtable_base() [with _Key = std::tuple<int, int, int>; _Value = std::pair<const std::tuple<int, int, int>, double>; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<std::tuple<int, int, int> >; _Hash = std::hash<std::tuple<int, int, int> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _Traits = std::__detail::_Hashtable_traits<true, false, true>]'
In file included from /usr/include/c++/14/bits/hashtable.h:35:
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: note: 'std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _Traits>::_Hashtable_base() [with _Key = std::tuple<int, int, int>; _Value = std::pair<const std::tuple<int, int, int>, double>; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<std::tuple<int, int, int> >; _Hash = std::hash<std::tuple<int, int, int> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _Traits = std::__detail::_Hashtable_traits<true, false, true>]' is implicitly deleted because the default definition would be ill-formed:
 1731 |       _Hashtable_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: error: use of deleted function 'std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash, _Unused, __cache_hash_code>::_Hash_code_base() [with _Key = std::tuple<int, int, int>; _Value = std::pair<const std::tuple<int, int, int>, double>; _ExtractKey = std::__detail::_Select1st; _Hash = std::hash<std::tuple<int, int, int> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; bool __cache_hash_code = true]'
/usr/include/c++/14/bits/hashtable_policy.h: In instantiation of 'std::__detail::_Hashtable_ebo_helper<_Nm, _Tp, true>::_Hashtable_ebo_helper() [with int _Nm = 1; _Tp = std::hash<std::tuple<int, int, int> >]':
/usr/include/c++/14/bits/hashtable_policy.h:1328:7:   required from here
 1328 |       _Hash_code_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1245:49: error: use of deleted function 'std::hash<std::tuple<int, int, int> >::hash()'
 1245 |       _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
      |                                                 ^~~~~
In file included from /usr/include/c++/14/string_view:50,
                 from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/functional_hash.h:102:12: note: 'std::hash<std::tuple<int, int, int> >::hash()' is implicitly deleted because the default definition would be ill-formed:
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:102:12: error: no matching function for call to 'std::__hash_enum<std::tuple<int, int, int>, false>::__hash_enum()'
/usr/include/c++/14/bits/functional_hash.h:83:7: note: candidate: 'std::__hash_enum<_Tp, <anonymous> >::__hash_enum(std::__hash_enum<_Tp, <anonymous> >&&) [with _Tp = std::tuple<int, int, int>; bool <anonymous> = false]'
   83 |       __hash_enum(__hash_enum&&);
      |       ^~~~~~~~~~~
/usr/include/c++/14/bits/functional_hash.h:83:7: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/functional_hash.h:102:12: error: 'std::__hash_enum<_Tp, <anonymous> >::~__hash_enum() [with _Tp = std::tuple<int, int, int>; bool <anonymous> = false]' is private within this context
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:84:7: note: declared private here
   84 |       ~__hash_enum();
      |       ^
/usr/include/c++/14/bits/hashtable_policy.h:1245:49: note: use '-fdiagnostics-all-candidates' to display considered candidates
 1245 |       _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
      |                                                 ^~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1328:7: note: 'std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash, _Unused, __cache_hash_code>::_Hash_code_base() [with _Key = std::tuple<int, int, int>; _Value = std::pair<const std::tuple<int, int, int>, double>; _ExtractKey = std::__detail::_Select1st; _Hash = std::hash<std::tuple<int, int, int> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; bool __cache_hash_code = true]' is implicitly deleted because the default definition would be ill-formed:
 1328 |       _Hash_code_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1328:7: error: use of deleted function 'std::__detail::_Hashtable_ebo_helper<1, std::hash<std::tuple<int, int, int> >, true>::~_Hashtable_ebo_helper()'
/usr/include/c++/14/bits/hashtable_policy.h:1242:12: note: 'std::__detail::_Hashtable_ebo_helper<1, std::hash<std::tuple<int, int, int> >, true>::~_Hashtable_ebo_helper()' is implicitly deleted because the default definition would be ill-formed:
 1242 |     struct _Hashtable_ebo_helper<_Nm, _Tp, true>
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1242:12: error: use of deleted function 'std::hash<std::tuple<int, int, int> >::~hash()'
/usr/include/c++/14/bits/functional_hash.h:102:12: note: 'std::hash<std::tuple<int, int, int> >::~hash()' is implicitly deleted because the default definition would be ill-formed:
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:102:12: error: 'std::__hash_enum<_Tp, <anonymous> >::~__hash_enum() [with _Tp = std::tuple<int, int, int>; bool <anonymous> = false]' is private within this context
/usr/include/c++/14/bits/functional_hash.h:84:7: note: declared private here
   84 |       ~__hash_enum();
      |       ^
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: note: use '-fdiagnostics-all-candidates' to display considered candidates
 1731 |       _Hashtable_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: error: use of deleted function 'std::__detail::_Hash_code_base<std::tuple<int, int, int>, std::pair<const std::tuple<int, int, int>, double>, std::__detail::_Select1st, std::hash<std::tuple<int, int, int> >, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, true>::~_Hash_code_base()'
/usr/include/c++/14/bits/hashtable_policy.h:1306:12: note: 'std::__detail::_Hash_code_base<std::tuple<int, int, int>, std::pair<const std::tuple<int, int, int>, double>, std::__detail::_Select1st, std::hash<std::tuple<int, int, int> >, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, true>::~_Hash_code_base()' is implicitly deleted because the default definition would be ill-formed:
 1306 |     struct _Hash_code_base
      |            ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1306:12: er