BigInteger operator - (const BigInteger& b) const { BigInteger c; c.s.resize(s.size()); for(int i = 0, g = 0; i < s.size(); i++) { c.s[i] = s[i] - g; g = 0; int sub = (i < b.s.size() ? b.s[i] : 0); if(c.s[i] < sub) { g = 1; c.s[i] += BASE; } c.s[i] -= sub; } c.adjust(); return c; }
BigInteger operator * (const BigInteger& b) const { BigInteger c; c.s.resize(s.size() + b.s.size() + 1); fill(c.s.begin(), c.s.end(), 0); for(int i = 0; i < s.size(); i++) for(int j = 0; j < b.s.size(); j++) { long long sum = (long long)s[i] * b.s[j] + c.s[i+j]; c.s[i+j+1] += sum / BASE; c.s[i+j] = sum % BASE; } c.adjust(); return c; }
BigInteger divmod (int b, int& d) const { BigInteger c; c.s.clear(); d = 0; for(int i = s.size()-1; i >= 0; i--) { long long v = (long long)d * BASE + s[i]; c.s.push_back(v / b); d = v % b; } reverse(c.s.begin(), c.s.end()); c.adjust(); return c; }