class Solution {
public:
#define ll long
#define atoll atol

	bool isAdditiveNumber(string num) {		
		_num = num;
		_flags  = vector<int>(num.size(), 0);
		_flags[0] = 1;

		dfs(1);

		return _ret;
	}

	void dfs(int i)
	{
		if (i == _num.size())
		{
			handle();
		}
		else
		{
			_flags[i] = 0;
			if(promise1(i))
				dfs(i + 1);

			_flags[i] = 1;
			if (promise2(i))
			dfs(i + 1);
		}
	}

	bool promise1(int index)
	{
		bool bb;
		vector<ll> vec = flag_to_vec(bb);
		if (bb == false) return false;

		if (vec.size() == 1 && index >= _num.size() - 2)
		{
			return false;
		}
		else if(vec.size() == 2)
		{
			if (vec[0] > vec[1]) return false;
		}

		return true;
	}

	bool promise2(int index)
	{
		vector<ll> vals;
		int pre = 0;
		for (size_t i = 1; i <= index; i++)
		{
			if (_flags[i])
			{
				string TMP(_num.begin() + pre, _num.begin() + i);

				//出现以0开头的数字
				if (TMP[0] == '0' && TMP.size() > 1)
				{
					return false;
				}

				vals.push_back(atoll(TMP.c_str()));
				pre = i;
			}
		}
		
		if (vals.size() >= 3)
		{
			ll p1 = vals[0], p2 = vals[1];
			
			for (int i = 2; i < vals.size(); i++)
			{
				if (vals[i] != p1 + p2)
				{
					for (int v : vals)
					{
						//cout << v << "\t";
					}
					//cout << "\n";
					return false;
				}
					
				p1 = p2, p2 = vals[i];
			}
		}

		return true;
	}

	vector<ll> flag_to_vec(bool& bb)
	{
		vector<ll> vals;
		int pre = 0;
		for (size_t i = 1; i < _flags.size(); i++)
		{
			if (_flags[i])
			{
				string TMP(_num.begin() + pre, _num.begin() + i);

				//出现以0开头的数字
				if (TMP[0] == '0' && TMP.size() > 1)
				{
					bb = false;
				}

				vals.push_back(atoll(TMP.c_str()));
				pre = i;
			}
		}

		string TMP(_num.begin() + pre, _num.end());
		vals.push_back(atoll(TMP.c_str()));

		//出现以0开头的数字
		if (TMP[0] == '0' && TMP.size() > 1)
		{
			bb = false;
		}

		return vals;
	}

	void handle()
	{
		bool bb = true;

		//if (_flags[0] == 1 &&  _flags[1] == 1 &&  _flags[11] == 1)
		//{
		//	//for (int v : vals)
		//	//{
		//	//	cout << v << "\t";
		//	//}
		//	//cout << "\n";
		//}

		vector<ll> vals = flag_to_vec(bb);

		if (bb && vals.size() >= 3)
		{
#ifdef PRINT
			for (int v : vals)
			{
				cout << v << "\t";
			}
			cout << "\n";
#endif
			ll p1 = vals[0], p2 = vals[1];

			for (size_t i = 2; i < vals.size(); i++)
			{
				if (vals[i] != p1 + p2)
				{
					break;
				}
				else
				{
					p1 = p2, p2 = vals[i];
				}

				if (i == vals.size() - 1)
				{
#ifdef PRINT
					cout << "==========\t";
					for (int v : vals)
					{
						cout  << v << "\t";
					}
					cout << "\n";
#endif
					_ret = true;
				}
			}
		}
	}

	bool _ret = false;
	vector<int> _flags;
	string _num;
};