Merkkijono

#include <iostream>
#include <string>
using namespace std;
int main()
{
	string back;
	string line;
	bool exist = true;
	getline(cin, line);
	while(exist == true)
	{ 
		if (line.length() == 0)
		{
			exist = false;
		}
		for (unsigned int i = 0; i < line.length(); i++)
		{
			if (line[i] == line[i + 1])
			{
				if (line[i + 1] == line[i + 2])
				{
					//cout << "Erased " << i << endl;
					line.erase(i, 1);
					break;

				}
				if (line[i + 1] != line[i + 2])
				{
					//cout << "Erased " << i << " and " << i + 1 << endl;
					line.erase(i, 2);
					break;
				}
			}
		}
		for (unsigned int x = 0; x < line.length(); x++)
		{
			if (line[x] == line[x + 1])
			{
				exist = true;
				break;
			}
			exist = false;
		}
	}
	cout << line << endl;

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED