Language: C++

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

string s, t;
vector<long long> v[1000];
long long ans = 0;
long long n;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(NULL);

	cin >> s;
	cin >> t;

	n = s.size();

	for(int i=0; i<s.size(); i++) {
		v[s[i] - 'a'].push_back(i);
	}

	for(int i=0; i<t.size(); i++) {
		int c = t[i] - 'a';

		if(v[c].size() == 0) {
			cout << -1;
			return 0;
		}

		vector<int>::iterator it = lower_bound(v[c].begin(), v[c].end(), ans % n );
		if(it != v[c].end()) {
			ans = *it + ans / n * n;
		}
		else {
			it = upper_bound(v[c].begin(), v[c].end(), ans % n - n);
			ans = *it + ans / n * n + n;
		}
	}

	cout << ans+1;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:30:55: error: conversion from '__normal_iterator<long long int*,vector<long long int>>' to non-scalar type '__normal_iterator<int*,vector<int>>' requested
   30 |                 vector<int>::iterator it = lower_bound(v[c].begin(), v[c].end(), ans % n );
      |                                            ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:31:23: error: no match for 'operator!=' (operand types are 'std::vector<int>::iterator' and 'std::vector<long long int>::iterator')
   31 |                 if(it != v[c].end()) {
      |                    ~~ ^~ ~~~~~~~~~~
      |                    |             |
      |                    |             __normal_iterator<long long int*,vector<long long int>>
      |                    __normal_iterator<int*,vector<int>>
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/bits/regex.h:1132:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1132 |     operator!=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1132:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/regex.h:1212:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator!=(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1212 |     operator!=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1212:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/regex.h:1305:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1305 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1305:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/regex.h:1379:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1379 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1379:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<long long int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/regex.h:1473:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1473 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1473:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/regex.h:1547:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1547 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1547:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<long long int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/regex.h:1647:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1647 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1647:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/regex.h:2213:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator!=(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2213 |     operator!=(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2213:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_pair.h:1052:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator!=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1052 |     operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1052:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::pair<_T1, _T2>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:455:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  455 |     operator!=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:455:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::reverse_iterator<_Iterator>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/stl_iterator.h:500:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  500 |     operator!=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:500:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::reverse_iterator<_Iterator>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1686 |     operator!=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::move_iterator<_IteratorL>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1753 |     operator!=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::move_iterator<_IteratorL>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
In file included from /usr/include/c++/14/bits/char_traits.h:42,
                 from /usr/include/c++/14/string:42,
                 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/postypes.h:197:5: note: candidate: 'template<class _StateT> bool std::operator!=(const fpos<_StateT>&, const fpos<_StateT>&)'
  197 |     operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:197:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::iterator' is not derived from 'const std::fpos<_StateT>'
   31 |                 if(it != v[c].end()) {
      |                                   ^
In file included from /usr/include/c++/14/string:43:
/usr/include/c++/14/bits/allocator.h:243:5: note: candidate: 'template<class _T1, class _T2> bool std::operator!=(const allocator<_CharT>&, const allocator<_T2>&)'
  243 |     operator!=(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:243:5: note:   template argument deduction/substitution failed:
a.cc:31:35: note:   'std::vector<int>::ite