Language: C++

#include <bits/stdc++.h>
using ull = unsigned __int128;
using namespace std;

const ull B = 100000007;

ull Rev(ull a) {
	ull res = 1;
	for (ull i = 0; i < 0x80; i++) {
		res *= a;
		a *= a;
	}
	return res;
}

ull Pow(ull a, ull b) {
	ull res = 1;
	for (ull i = 0; i < 0x80;i++) {
		if (b & (1ull << i)) {
			res *= a;
		}
		a *= a;
	}
	return res;
}

int main()
{
	ull n, m, l = 0, r = 0;
	ull hash;
	string S, cmd;
	set<ull> hass;
	cin.sync_with_stdio(false);
	cin >> n >> m >> S;
	hash = S[0];
	while (m--) {
		cin >> cmd;
		if (cmd == "L++") {
			hash -= Pow(B, r - l) * S[l];
			l++;
		}
		else if (cmd == "L--") {
			l--;
			hash += Pow(B, r - l) * S[l];
		}
		else if (cmd == "R++") {
			r++;
			hash = hash * B + S[r];
		}
		else if (cmd == "R--") {
			hash = (hash - S[r]) * Rev(B);
			r--;
		}
		hass.insert(hash);
	}
	cout << hass.size() << endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:34:13: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'ull' {aka '__int128 unsigned'})
   34 |         cin >> n >> m >> S;
      |         ~~~ ^~ ~
      |         |      |
      |         |      ull {aka __int128 unsigned}
      |         std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:1:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'short int&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'short unsigned int&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'int&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'unsigned int&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'long int&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'long unsigned int&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'long long int&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'long long unsigned int&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'float&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'double&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: cannot bind non-const lvalue reference of type 'long double&' to a value of type 'ull' {aka '__int128 unsigned'}
   34 |         cin >> n >> m >> S;
      |                ^
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: invalid conversion from 'ull' {aka '__int128 unsigned'} to 'void*' [-fpermissive]
   34 |         cin >> n >> m >> S;
      |                ^
      |                |
      |                ull {aka __int128 unsigned}
a.cc:34:16: error: cannot bind rvalue '(void*)((long int)n)' to 'void*&'
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: invalid conversion from 'ull' {aka '__int128 unsigned'} to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'} [-fpermissive]
   34 |         cin >> n >> m >> S;
      |                ^
      |                |
      |                ull {aka __int128 unsigned}
/usr/include/c++/14/istream:126:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>; __ios_type = std::basic_ios<char>]' (near match)
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:126:7: note:   conversion of argument 1 would be ill-formed:
a.cc:34:16: error: invalid conversion from 'ull' {aka '__int128 unsigned'} to 'std::basic_istream<char>