Language: C++

#include<vector>
#include<string>
#include<map>
#include<fstream>
#include<iostream>
#include<cmath>
using namespace std;

string str;
map<string,int> Idx;
int atom=0;
int pos=0;
int num=0;
bool rev;

vector<int> read(){
	vector<int> res(atom,0);
	if(str.size()<=pos || str[pos]=='+' || str[pos]=='.' || str[pos]==')' || str[pos]=='-'){return res;}
	string temp="";
	if(isupper(str[pos])){
		temp+=str[pos++];
		if(islower(str[pos]))
			temp+=str[pos++];
		res[Idx[temp]]+=1;
	}
	else if(str[pos]=='('){
		pos++;
		res=read();
		pos++;
	}
	int mul=1;
	if(isdigit(str[pos])){
		mul=str[pos++]-'0';
		if(isdigit(str[pos]))
			mul=mul*10+str[pos++]-'0';
	}
	vector<int> next;
	next=read();
	for(int i=0;i<res.size();i++)
		res[i]=res[i]*mul+next[i];
	return res;
}


int gcd(int a, int b){ return a%b ? gcd(b, a%b) : b; }
int lcm(int a, int b){ return a/gcd(a,b)*b; }

int main()
{
	ifstream fin("F.in");
	while(cin>>str){
		if(str==".") break;
		atom=0;
		pos=0;
		num=2;
		rev=false;
		Idx.clear();
		for(int i=0;i<str.size();i++){
			string temp="";
			if(str[i]=='+')
				num++;
			if(isupper(str[i])){
				temp+=str[i];
				if(i+1<str.size() && islower(str[i+1]))
					temp+=str[++i];
			}
			if(temp!="" && !Idx.count(temp))
				Idx[temp]=atom++;
		}
		vector<vector<int> > v(atom,0);
		for(int i=0;i<num;i++){
			if(str[pos]=='+')
				pos++;
			if(str[pos]=='-'){
				pos+=2;
				rev=true;
			}
			vector<int> temp=read();
			for(int j=0;j<temp.size();j++)
				v[j].push_back(!rev ? temp[j]:-temp[j]);
		}
		for(int i=0;i<v[0].size()-1;i++){
			if(v[i][i]==0){
				int idx=i;
				while(!v[idx][i]) idx++;
				swap(v[i],v[idx]);
			}
			for(int j=0;j<v.size();j++){
				if(v[j][i]==0 || i==j) continue;
				int mula=v[i][i]/gcd(v[i][i],v[j][i]);
				int mulb=v[j][i]/gcd(v[i][i],v[j][i]);
				for(int k=0;k<v[0].size();k++)	v[j][k]=v[j][k]*mula-v[i][k]*mulb;
			}
			for(int j=0;j<v.size();j++){
				int div=0;
				for(int k=0;k<v[0].size();k++)
					if(v[j][k]!=0) div=!div ? abs(v[j][k]):gcd(abs(v[j][k]),div);
				if(div)
					for(int k=0;k<v[0].size();k++)	v[j][k]/=div;
			}
		}

		int mul=1;
		for(int i=0;i<num-1;i++)
			mul=lcm(mul,abs(v[i][i]));
		for(int i=0;i<num-1;i++)
			cout<<abs(v[i][num-1]*mul/v[i][i])<<" ";
		cout<<mul<<endl;

	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:70:46: error: no matching function for call to 'std::vector<std::vector<int> >::vector(int&, int)'
   70 |                 vector<vector<int> > v(atom,0);
      |                                              ^
In file included from /usr/include/c++/14/vector:66,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_vector.h:707:9: note: candidate: 'template<class _InputIterator, class> std::vector<_Tp, _Alloc>::vector(_InputIterator, _InputIterator, const allocator_type&) [with <template-parameter-2-2> = _InputIterator; _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  707 |         vector(_InputIterator __first, _InputIterator __last,
      |         ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:707:9: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/14/bits/stl_algobase.h:65,
                 from /usr/include/c++/14/vector:62:
/usr/include/c++/14/bits/stl_iterator_base_types.h: In substitution of 'template<class _InIter> using std::_RequireInputIter = std::__enable_if_t<((bool)std::is_convertible<typename std::iterator_traits< <template-parameter-1-1> >::iterator_category, std::input_iterator_tag>::value)> [with _InIter = int]':
/usr/include/c++/14/bits/stl_vector.h:705:9:   required from here
  705 |                typename = std::_RequireInputIter<_InputIterator>>
      |                ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator_base_types.h:252:57: error: no type named 'iterator_category' in 'struct std::iterator_traits<int>'
  252 |                                    input_iterator_tag>::value>;
      |                                                         ^~~~~
/usr/include/c++/14/bits/stl_vector.h:678:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >]'
  678 |       vector(initializer_list<value_type> __l,
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:678:43: note:   no known conversion for argument 1 from 'int' to 'std::initializer_list<std::vector<int> >'
  678 |       vector(initializer_list<value_type> __l,
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:659:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, std::__type_identity_t<_Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; std::__type_identity_t<_Alloc> = std::allocator<std::vector<int> >]'
  659 |       vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:659:23: note:   no known conversion for argument 1 from 'int' to 'std::vector<std::vector<int> >&&'
  659 |       vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
      |              ~~~~~~~~~^~~~
/usr/include/c++/14/bits/stl_vector.h:640:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, const allocator_type&, std::false_type) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >; std::false_type = std::false_type]'
  640 |       vector(vector&& __rv, const allocator_type& __m, false_type)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:640:7: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_vector.h:635:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, const allocator_type&, std::true_type) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >; std::true_type = std::true_type]'
  635 |       vector(vector&& __rv, const allocator_type& __m, true_type) noexcept
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:635:7: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_vector.h:624:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&, std::__type_identity_t<_Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; std::__type_identity_t<_Alloc> = std::allocator<std::vector<int> >]'
  624 |       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:624:28: note:   no known conversion for argument 1 from 'int' to 'const std::vector<std::vector<int> >&'
  624 |       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
      |              ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:620:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  620 |       vector(vector&&) noexcept = default;
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:620:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:601:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  601 |       vector(const vector& __x)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:601:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:569:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(size_type, const value_type&, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; size_type = long unsigned int; value_type = std::vector<int>; allocator_type = std::allocator<std::vector<int> >]'
  569 |       vector(size_type __n, const value_type& __value,
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:569:47: note:   no known conversion for argument 2 from 'int' to 'const std::vector<std::vector<int> >::value_type&' {aka 'const std::vector<int>&'}
  569 |       vector(size_type __n, const value_type& __value,
      |                             ~~~~~~~~~~~~~~~~~~^~~~~~~
/usr/include/c++/14/bits/stl_vector.h:556:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(size_type, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; size_type = long unsigned int; allocator_type = std::allocator<std::vector<int> >]'
  556 |       vector(size_type __n, const allocator_type& __a = allocator_type())
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:556:51: note:   no known conversion for argument 2 from 'int' to 'const std::vector<std::vector<int> >::allocator_type&' {aka 'const std::allocator<std::vector<int> >&'}
  556 |       vector(size_type __n, const allocator_type& __a = allocator_type())
      |                             ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:542:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >]'
  542 |       vector(const allocator_type& __a) _GLIBCXX_NOEXCEPT
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:542:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:531:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector() [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  531 |       vector() = default;
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:531:7: note:   candidate expects 0 arguments, 2 provided