Language: C++

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<numeric>
#include<map>
#include<unordered_map>
#include<set>
#include<stack>
#include<queue>
#include<sstream>
#include<iomanip>

#define reps(i,j,k) for(int i=(j);i<(k);i++)
#define rep(i,j) reps(i,0,j)
#define fs first
#define sc second
#define pb push_back
#define mk make_pair

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<short> vi;

template<class S,class T>
ostream &operator<<(ostream &out, const pair<S,T> p){
	return out << "(" << p.fs << ", " << p.sc << ")";
}

template<class T>
ostream &operator<<(ostream &out, const vector<T> &v){
	out << "{";
	rep(i,v.size()) out << v[i] << ", ";
	return out << "}" << endl;
}

vi operator-(const vi &a, const vi &b){
	vi ret(26);
	rep(i, 26) ret[i] = a[i] - b[i];
	return ret;
}

bool operator==(const vi &a, const vi &b){
	rep(i, 26) if (a[i] != b[i]) return false;
	return true;
}

vector<vi> ss, tt;
set<vi> st;
int main(){
	string s, t;
	cin >> s >> t;
	vi tmp(26);
	ss.pb(tmp);
	tt.pb(tmp);
	rep(i,s.length()){
		tmp[s[i] - 'a'] ++;
		ss.pb(tmp);
	}
	tmp.resize(0);
	tmp.resize(26);
	rep(i,t.length()){
		tmp[t[i] - 'a'] ++;
		tt.pb(tmp);
	}

	rep(i, t.length()+1){
		reps(j, i+1, t.length()+1){
			vi sub = tt[j] - tt[i];
			st.insert(sub);
		}
	}
	sort(st.begin(), st.end());

	int ans = 0;
	rep(i, s.length()+1){
		reps(j, i+1, s.length()+1){
			vi sub = ss[j] - ss[i];
			int len = j - i;
			auto it = lower_bound(st.begin(), st.end(), sub);
			if(it == st.end()) continue;
			if(*it == sub){
				ans = max(ans, len);
			}
		}
	}
	cout << ans << endl;
	return 0;
}



Compiler output:
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:4:
/usr/include/c++/14/bits/stl_algo.h: In instantiation of 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = _Rb_tree_const_iterator<vector<short int> >; _Compare = __gnu_cxx::__ops::_Iter_less_iter]':
/usr/include/c++/14/bits/stl_algo.h:4772:18:   required from 'void std::sort(_RAIter, _RAIter) [with _RAIter = _Rb_tree_const_iterator<vector<short int> >]'
 4772 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:74:6:   required from here
   74 |         sort(st.begin(), st.end());
      |         ~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1906:50: error: no match for 'operator-' (operand types are 'std::_Rb_tree_const_iterator<std::vector<short int> >' and 'std::_Rb_tree_const_iterator<std::vector<short int> >')
 1906 |                                 std::__lg(__last - __first) * 2,
      |                                           ~~~~~~~^~~~~~~~~
In file included from /usr/include/c++/14/string:48,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:618:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr decltype ((__y.base() - __x.base())) std::operator-(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  618 |     operator-(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:618:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:1906:50: note:   'std::_Rb_tree_const_iterator<std::vector<short int> >' is not derived from 'const std::reverse_iterator<_Iterator>'
 1906 |                                 std::__lg(__last - __first) * 2,
      |                                           ~~~~~~~^~~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1790:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr decltype ((__x.base() - __y.base())) std::operator-(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1790 |     operator-(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1790:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:1906:50: note:   'std::_Rb_tree_const_iterator<std::vector<short int> >' is not derived from 'const std::move_iterator<_IteratorL>'
 1906 |                                 std::__lg(__last - __first) * 2,
      |                                           ~~~~~~~^~~~~~~~~