int correlation(const String& a, const String& b)
{
	int res=0;
	const char* A = a.Begin();
	const char* B = b.Begin();

	const int Al = a.GetLength();
	const int Bl = b.GetLength();
	const int deltaL = Al - Bl;

	int As, Bs, intersectLength;
	int subRes;

	int matchPatternMinLength = max(2, min(b.GetLength(), a.GetLength())/3);


	for (int offset = (matchPatternMinLength-Bl); offset <= (Al-matchPatternMinLength); offset++ )
	{
		// range calculation
		if (offset < 0)
		{
			As = 0;
			Bs = -offset;
			if (offset < deltaL) intersectLength = offset + Bl;
			else                 intersectLength = Al;
		}
		else
		{
			As = offset;
			Bs = 0;
			intersectLength = Al - offset;
			if (offset <= deltaL) intersectLength = Bl;
			else                  intersectLength = Al-offset;
		}

		subRes = 0;
		for (int c = 0; c<intersectLength; c++)
		{
			if( A[As+c] == B[Bs+c]) ++subRes;
		}
		if (subRes >= matchPatternMinLength) res += subRes;
	}

	// taking string length in account
	if ( deltaL > 0 )
	{
		res -= deltaL;
	}
	else
	{
		res += deltaL;
	}
	return res;
}


inline bool CompareDistance(const String& a, const String& b)
{
	if (correlation(a, b) >= max(2, min(a.GetLength(), b.GetLength())*3/5)) return true;
	return false;
}

 CompareDistance() 

 CompareDistance(stringA, stringB)