BigInt BigInt::operator -(const BigInt& right) const
{
BigInt left = *this;
if (left.sign != right.sign)
{
return left - (-right);
}
if (this->abs() >= right.abs())
{
BigInt res = left;
int carry = 0;
for (int i = 0; i < right.number.size() || carry; ++i)
{
res.number[i] -= carry + (i < right.number.size() ? right.number[i] : 0);
carry = res.number[i] < 0;
if (carry)
{
res.number[i] += BigInt::base;
}
}
res.RemoveZero();
return res;
}
else
{
return -(right - left);
}
}
BigInt BigInt::operator *(const BigInt& right) const
{
BigInt left = *this;
BigInt res;
res.sign = left.sign * right.sign;
res.number.resize(right.number.size() + left.number.size() + 1);
for (int i = 0; i < left.number.size(); i++)
{
for (int j = 0, carry = 0; j < right.number.size() || carry; j++)
{
long long buf = res.number[i + j] + left.number[i] * 1ll * (j < right.number.size() ? right.number[j] : 0) + carry;
res.number[i + j] = (int)(buf % BigInt::base);
carry = (int)(buf / BigInt::base);
}
}
res.RemoveZero();
return res;
}
