高精度(加减乘除)

高精度加法

#include 
#include 
#include 
using namespace std;

vector add(vector &A, vector &B) {
	vector C;
	int t = 0;
	if (A.size() < B.size())
		return add(B, A);
	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(1);
	return C;
}

int main() {
	string a, b;
	cin >> a >> b;

	vector A, B;
	for (int i = a.size() - 1; i >= 0; i -- )
		A.push_back(a[i] - '0');
	for (int i = b.size() - 1; i >= 0; i -- )
		B.push_back(b[i] - '0');

	vector C = add(A, B);

	for (int i = C.size() - 1; i >= 0; i -- )
		cout << C[i];

	return 0;
}

高精度减法

#include 
#include 
#include 
using namespace std;

bool cmp(vector &A, vector &B) {
	if (A.size() != B.size())
		return A.size() >= B.size();
	for (int i = A.size() - 1; i >= 0; i -- )
		if (A[i] != B[i])
			return A[i] >= B[i];
	return true;
}

vector sub(vector &A, vector &B) {
	vector 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;
}

int main() {
	string a, b;
	cin >> a >> b;

	vector A, B;
	for (int i = a.size() - 1; i >= 0; i -- )
		A.push_back(a[i] - '0');
	for (int i = b.size() - 1; i >= 0; i -- )
		B.push_back(b[i] - '0');

	vector C;
	if (cmp(A, B))
		C = sub(A, B);
	else {
		C = sub(B, A);
		cout << '-';
	}
	for (int i = C.size() - 1; i >= 0; i -- )
		cout << C[i];

	return 0;
}

高精度乘法(高精度乘低精度)

#include 
#include 
#include 
using namespace std;

vector mul(vector &A,	int b) {
	vector C;
	for (int i = 0, t = 0; i < A.size() || t; i ++ ) {
		if (i < A.size())
			t += A[i] * b;
		C.push_back(t % 10);
		t /= 10;
	}
	while (C.size() > 1 && C.back() == 0)
		C.pop_back();
	return C;
}

int main() {
	string a;
	int b;
	cin >> a >> b;

	vector A;
	for (int i = a.size() - 1; i >= 0; i -- )
		A.push_back(a[i] - '0');

	vector C;
	C = mul(A, b);
	for (int i = C.size() - 1; i >= 0; i -- )
		cout << C[i];

	return 0;
}

高精度乘法(高精度乘高精度)

(暴力是O(n^2)的，还有一个FFT的算法让时间费用更低，但是奈何本蒟蒻实在是不会啊~QAQ)

#include
using namespace std;
const int N = 1e5+10,M= 2e5+10;
int a[M],b[M],l1,l2;
char s[N];
void print(int a[])
{
    int k=M-1;
    while(k && !a[k]) k--;
    for(int i=k;i>=0;i--) cout<

#include 
#include 
#include 
#include 
using namespace std;
vector div(vector &A, int b)
{
    vector C;
    int t = 0;
    for(int i = A.size() - 1; i >= 0; i -- )
    {
        t = t * 10 + A[i];
        C.push_back(t / b);
        t %= b;
    }
    reverse(C.begin(), C.end());
    while(C.size() > 1 && C.back() == 0) C.pop_back();
    return C;
}
int main()
{
    string a;
    int b;
    cin >> a >> b;
    vector A;
    for(int i = a.size() - 1; i >= 0; i -- ) A.push_back(a[i] - '0');
    vector C;
    C = div(A,b);
    for(int i = 0; i < C.size(); i ++ )
        cout << C[i];
    return 0;
}