// 高精度加法
// C = A + B, A >= 0, B >= 0
vector<int> add(vector<int> &A, vector<int> &B)
{if (A.size() < B.size()) return add(B, A);vector<int> C;int t = 0;for (int i = 0; i < A.size(); i ++ ){t += A[i];if (i < B.size()) t += B[i];C.push_back(t % 10);t /= 10;}if (t) C.push_back(t);return C;
}// 高精度减法
// C = A - B, 满足A >= B, A >= 0, B >= 0
vector<int> sub(vector<int> &A, vector<int> &B)
{vector<int> C;for (int i = 0, t = 0; i < A.size(); i ++ ){t = A[i] - t;if (i < B.size()) t -= B[i];C.push_back((t + 10) % 10);if (t < 0) t = 1;else t = 0;}while (C.size() > 1 && C.back() == 0) C.pop_back();return C;
}// 高精度乘低精度
// C = A * b, A >= 0, b > 0
vector<int> mul(vector<int> &A, int b)
{vector<int> C;int t = 0;for (int i = 0; i < A.size() || t; i ++ ){if (i < A.size()) t += A[i] * b;C.push_back(t % 10);t /= 10;}return C;
}// 高精度除以低精度
// A / b = C ... r, A >= 0, b > 0
vector<int> div(vector<int> &A, int b, int &r)
{vector<int> C;r = 0;for (int i = A.size() - 1; i >= 0; i -- ){r = r * 10 + A[i];C.push_back(r / b);r %= b;}reverse(C.begin(), C.end());while (C.size() > 1 && C.back() == 0) C.pop_back();return C;
}