Language: C++

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef pair<ll, ll> hashVal;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int K = 26;
const ll mod1 = 1e9 + 7;
const ll mod2 = 1e9 + 9;

inline hashVal operator+(hashVal a, hashVal b){
	ll x = a.first + b.first; if(x >= mod1)x -= mod1;
	ll y = a.second + b.second; if(y >= mod2)y -= mod2;
	return {x, y};
}

inline hashVal operator-(hashVal a, hashVal b){
	ll x = a.first - b.first; if(x < 0)x += mod1;
	ll y = a.second - b.second; if(y < 0)y += mod2;
	return {x, y};
}

inline hashVal operator*(hashVal a, hashVal b){
	return {a.first*b.first%mod1, a.second*b.second%mod2};
}

inline hashVal operator*(hashVal a, ll k){
	return {a.first*k%mod1, a.second*k%mod2};
}

inline hashVal operator*(ll k, hashVal a){
	return {a.first*k%mod1, a.second*k%mod2};
}

hashVal base, val[K];

void pre(){
	base = {0, 0};
	while(base.first == 0 || base.second == 0){
		base = {rng()%mod1, rng()%mod2};
	}
	for(int i = 0; i < K; i++){
		val[i] = {0, 0};
		while(val[i].first == 0 || val[i].second == 0){
			val[i] = {rng()%mod1, rng()%mod2};
			for(int j = 0; j < i; j++){
				if(val[i].first == val[j].first || val[i].second == val[j].second){
					val[i] = {0, 0};
					break;
				}
			}
			if(val[i].first == base.first || val[i].second == base.second){
				val[i] = {0, 0};
			}
		}
	}
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	cout<<setprecision(32);

	pre();
	int n; cin>>n;
	vector<string> v(n);
	for(auto &x : v){
		cin>>x;
	}
	sort(v.begin(), v.end(), [](string &a, string &b){
		return a.size() < b.size();
	});
	unordered_map<hashVal, int> mp;
	ll ans = 0;
	for(int i = 0; i < n; i++){
		reverse(v[i].begin(), v[i].end());
		vector<int> f(K);
		for(auto ch : v[i]){
			f[ch - 'a']++;
		}
		int sz = v[i].size();
		hashVal hv = {0, 0};
		for(int j = 0; j < sz; j++){
			for(int k = 0; k < K; k++){
				if(f[k]){
					hashVal tmp = hv*base + val[k];
					if(mp.count(tmp))ans += mp[tmp];
				}
			}
			f[v[i][j] - 'a']--;
			hv = hv*base + val[v[i][j] - 'a'];
		}
		mp[hv]++;
	}
	cout<<ans;


	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:77:37: error: use of deleted function 'std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map() [with _Key = std::pair<long long int, long long int>; _Tp = int; _Hash = std::hash<std::pair<long long int, long long int> >; _Pred = std::equal_to<std::pair<long long int, long long int> >; _Alloc = std::allocator<std::pair<const std::pair<long long int, long long int>, int> >]'
   77 |         unordered_map<hashVal, int> mp;
      |                                     ^~
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:1:
/usr/include/c++/14/bits/unordered_map.h:148:7: note: 'std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map() [with _Key = std::pair<long long int, long long int>; _Tp = int; _Hash = std::hash<std::pair<long long int, long long int> >; _Pred = std::equal_to<std::pair<long long int, long long int> >; _Alloc = std::allocator<std::pair<const std::pair<long long int, long long int>, int> >]' 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::pair<long long int, long long int>; _Value = std::pair<const std::pair<long long int, long long int>, int>; _Alloc = std::allocator<std::pair<const std::pair<long long int, long long int>, int> >; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<std::pair<long long int, long long int> >; _Hash = std::hash<std::pair<long long int, long long 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::pair<long long int, long long int>; _Value = std::pair<const std::pair<long long int, long long int>, int>; _Alloc = std::allocator<std::pair<const std::pair<long long int, long long int>, int> >; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<std::pair<long long int, long long int> >; _Hash = std::hash<std::pair<long long int, long long 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::pair<long long int, long long int>; _Value = std::pair<const std::pair<long long int, long long int>, int>; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<std::pair<long long int, long long int> >; _Hash = std::hash<std::pair<long long int, long long 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::pair<long long int, long long int>; _Value = std::pair<const std::pair<long long int, long long int>, int>; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<std::pair<long long int, long long int> >; _Hash = std::hash<std::pair<long long int, long long 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::pair<long long int, long long int>; _Value = std::pair<const std::pair<long long int, long long int>, int>; _ExtractKey = std::__detail::_Select1st; _Hash = std::hash<std::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long int>; _Value = std::pair<const std::pair<long long int, long long int>, int>; _ExtractKey = std::__detail::_Select1st; _Hash = std::hash<std::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long int> >::~hash()'
/usr/include/c++/14/bits/functional_hash.h:102:12: note: 'std::hash<std::pair<long long int, long long 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::pair<long long int, long long 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::pair<long long int, long long int>, std::pair<const std::pair<long long int, long long int>, int>, std::__detail::_Select1st, std::hash<std::pair<long long int, long long int> >, std::__detail::_Mod_range_hashing, std::__detail::_Default_range