Long arithmetic : SUM

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

struct Node {
	int value;
	Node* next = NULL;
};

Node* first = NULL;
Node* second = NULL;
Node* res = NULL;


void Push(int value,Node**head) {
	Node* temp = new Node;
	temp->value = value;
	temp->next = (*head);
	(*head) = temp;
}

void print(Node* head) {
	Node* temp = head;
	while (temp->next != NULL) {
		cout << temp->value;
		temp = temp->next;
	}
	cout << temp->value;
}



string split(string & str) {
	//I haven't taken into consideration the case when the number is minus
	if (str.length() > 10) {
		int len = 10;
		string x1, x2;
		for (int i = 0; i < len; i++)

			x1.push_back(str[i]);


		for (int i = len; i < str.length(); i++)

			x2.push_back(str[i]);

		str = x2;
		return x1;
	}
	else {
		string x1;
		for (int i = 0; i < str.length(); i++)

			x1.push_back(str[i]);
		str.clear();
		return x1;
	}
}




int ConvertedToInt(string s) {
	//this should work fine, my only concern that it might take too long.
	int sum = 0;
	if (s[0] == '-') {
		for (int i = 1; i < s.length(); i++) {


			sum = sum * 10 + (s[i] - '0');

		}
		sum = sum * (-1);
	}
	else {
		for (int i = 0; i < s.length(); i++) {


			sum = sum * 10 + (s[i] - '0');

		}


	}
	return sum;
}
string RemoveSpaces(string str)

{
	for (int i = 0; i < str.length();) {
		if (str[i] == ' ') {
			str.erase(str.begin() + i);

		}
		else {
			i++;
		}
		}
		return str;
	}


Node* SUM(Node*first, Node* second) {
	Node* temp=new Node, * prev = NULL;
	int sum,  carry = 0;
	while(first != NULL || second != NULL) //termenating condition
	{
		//the sum will equal the carry + value from first list (if existes) if not put 0
		//, same for second if statment.
		sum = carry + (first ? first->value : 0) + (second ? second->value : 0);

		carry = (sum >= 10000000000) ? 1 : 0; //since we are didviding the numbers' digits by 10

		sum = sum % 10000000000;

		Node* NewNode = new Node;
		NewNode->value = sum;
		temp=NewNode;

		if (res == NULL) res = temp;

		else Push(sum,&res);

		prev = temp; //setting prev for next iteration

		//Moving forward in our lists
		if (first) first = first->next;
		if (second) second = second->next;

	}

	if (carry > 0) {
		Node* tempr = new Node;
		tempr->value = carry;
		tempr->next = NULL;
		temp->next = tempr;

	}
	return res;
}

int main() {
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);

	string s1, s2;
	int L1, L2;
	cin >> L1 >> L2;
	getline(cin, s1);
	getline(cin, s1);
	getline(cin, s2);
	s1=RemoveSpaces(s1);
	s2=RemoveSpaces(s2);
	if (s1.length() > s2.length()) {
		s2.insert(s2.begin() + 0, s1.length()-1, '0');
	}
	if (s1.length() < s2.length()) {
		s1.insert(s1.begin() + 0, s2.length() - 1, '0');
	}
	int temp;
	while (s1.length()>10) {
		temp = ConvertedToInt(split(s1));
		Push(temp,&first);
	}
	temp = ConvertedToInt(split(s1));
	Push(temp, &first);
	while (s2.length() > 10) {
		temp = ConvertedToInt(split(s2));
		Push(temp,&second);
	}
	temp = ConvertedToInt(split(s2));
	Push(temp, &second);
	print(SUM(first, second));
	return 0;


}