Language: C++

#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

int N,ans = 0;
bool flag = true;

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin >> N;
	vector<int> A(N),B(N),dif(N);
	for(auto &x: A){
		cin >> x;	
	}
	for(auto &x: B){
		cin >> x;	
	}

	REP(i,N){
		if(A[i] < B[i]) flag = false;
		dif[i] = B[i] - A[i];
	}
	sort(dif.begin(),dif.end());
	if(0 > accumulate(dif.begin(),dif.end(),0)){
		cout << -1 << endl;
	}else if(flag){
		cout << 0 << endl;
	}else{
		while(dif[0] < 0){
			int t = *dif[N - 1];
			ans++;
			dif.end() = 0;
			auto it = dif.begin();
			while(t){
				if(dif[it]*-1 >= t){
					dif[it] -= 0;
					t = 0;
				}else{
					t -= dif[it]*-1;
					dif[it] = 0;
					it++;
				}
			}
			sort(dif.begin(),dif.end());
		}
		cout << ans << endl;
	}


}

Compiler output:
a.cc: In function 'int main()':
a.cc:33:33: error: invalid type argument of unary '*' (have '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'})
   33 |                         int t = *dif[N - 1];
a.cc:35:37: error: no match for 'operator=' (operand types are 'std::vector<int>::iterator' and 'int')
   35 |                         dif.end() = 0;
      |                                     ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:1038:11: note: candidate: 'constexpr __gnu_cxx::__normal_iterator<int*, std::vector<int> >& __gnu_cxx::__normal_iterator<int*, std::vector<int> >::operator=(const __gnu_cxx::__normal_iterator<int*, std::vector<int> >&)'
 1038 |     class __normal_iterator
      |           ^~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1038:11: note:   no known conversion for argument 1 from 'int' to 'const __gnu_cxx::__normal_iterator<int*, std::vector<int> >&'
/usr/include/c++/14/bits/stl_iterator.h:1038:11: note: candidate: 'constexpr __gnu_cxx::__normal_iterator<int*, std::vector<int> >& __gnu_cxx::__normal_iterator<int*, std::vector<int> >::operator=(__gnu_cxx::__normal_iterator<int*, std::vector<int> >&&)'
/usr/include/c++/14/bits/stl_iterator.h:1038:11: note:   no known conversion for argument 1 from 'int' to '__gnu_cxx::__normal_iterator<int*, std::vector<int> >&&'
a.cc:38:39: error: no match for 'operator[]' (operand types are 'std::vector<int>' and '__gnu_cxx::__normal_iterator<int*, std::vector<int> >')
   38 |                                 if(dif[it]*-1 >= t){
      |                                       ^
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53:
/usr/include/c++/14/bits/stl_vector.h:1128:7: note: candidate: 'std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = int; _Alloc = std::allocator<int>; reference = int&; size_type = long unsigned int]'
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1128:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' to 'std::vector<int>::size_type' {aka 'long unsigned int'}
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:1147:7: note: candidate: 'std::vector<_Tp, _Alloc>::const_reference std::vector<_Tp, _Alloc>::operator[](size_type) const [with _Tp = int; _Alloc = std::allocator<int>; const_reference = const int&; size_type = long unsigned int]'
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1147:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' to 'std::vector<int>::size_type' {aka 'long unsigned int'}
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
a.cc:39:44: error: no match for 'operator[]' (operand types are 'std::vector<int>' and '__gnu_cxx::__normal_iterator<int*, std::vector<int> >')
   39 |                                         dif[it] -= 0;
      |                                            ^
/usr/include/c++/14/bits/stl_vector.h:1128:7: note: candidate: 'std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = int; _Alloc = std::allocator<int>; reference = int&; size_type = long unsigned int]'
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1128:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' to 'std::vector<int>::size_type' {aka 'long unsigned int'}
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:1147:7: note: candidate: 'std::vector<_Tp, _Alloc>::const_reference std::vector<_Tp, _Alloc>::operator[](size_type) const [with _Tp = int; _Alloc = std::allocator<int>; const_reference = const int&; size_type = long unsigned int]'
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1147:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' to 'std::vector<int>::size_type' {aka 'long unsigned int'}
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
a.cc:42:49: error: no match for 'operator[]' (operand types are 'std::vector<int>' and '__gnu_cxx::__normal_iterator<int*, std::vector<int> >')
   42 |                                         t -= dif[it]*-1;
      |                                                 ^
/usr/include/c++/14/bits/stl_vector.h:1128:7: note: candidate: 'std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = int; _Alloc = std::allocator<int>; reference = int&; size_type = long unsigned int]'
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1128:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' to 'std::vector<int>::size_type' {aka 'long unsigned int'}
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:1147:7: note: candidate: 'std::vector<_Tp, _Alloc>::const_reference std::vector<_Tp, _Alloc>::operator[](size_type) const [with _Tp = int; _Alloc = std::allocator<int>; const_reference = const int&; size_type = long unsigned int]'
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1147:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' to 'std::vector<int>::size_type' {aka 'long unsigned int'}
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
a.cc:43:44: error: no match for 'operator[]' (operand types are 'std::vector<int>' and '__gnu_cxx::__normal_iterator<int*, std::vector<int> >')
   43 |                                         dif[it] = 0;
      |                                            ^
/usr/include/c++/14/bits/stl_vector.h:1128:7: note: candidate: 'std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = int; _Alloc = std::allocator<int>; reference = int&; size_type = long unsigned int]'
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1128:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' to 'std::vector<int>::size_type' {aka 'long unsigned int'}
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:1147:7: note: candidate: 'std::vector<_Tp, _Alloc>::const_reference std::vector<_Tp, _Alloc>::operator[](size_type) const [with _Tp = int; _Alloc = std::allocator<int>; const_reference = const int&; size_type = long unsigned int]'
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1147:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' to 'std::vector<int>::size_type' {aka 'long unsigned int'}
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~