手写高精

实际上只用写 (高精x低精) 和 (高精+=高精)

#include <bits/stdc++.h>
using namespace std;
int MAXLEN = 10000;
int n, m;
vector<int> a, b;
// now*=x (x!=0)
void mul(vector<int> &now, int x)
{
    // 乘
    for (int i = 0; i < now.size(); i++)
        now[i] *= x;
    // 进位
    for (int i = 1; i < now.size(); i++)
    {
        now[i] += now[i - 1] / 10;
        now[i - 1] %= 10;
    }
    while (now.back() >= 10)
    {
        now.push_back(now.back() / 10);
        now[now.size() - 2] %= 10;
    }
}
// a+=b
void add(vector<int> &a, vector<int> &b)
{
    // 补位
    while (a.size() < b.size())
        a.push_back(0);
    // 相加
    for (int i = 0; i < b.size(); i++)
        a[i] += b[i];
    // 进位
    for (int i = 1; i < a.size(); i++)
    {
        a[i] += a[i - 1] / 10;
        a[i - 1] %= 10;
    }
    while (a.back() >= 10)
    {
        a.push_back(a.back() / 10);
        a[a.size() - 2] %= 10;
    }
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m;
    a.push_back(1); // a=1
    b.push_back(1); // b=1
    // A(n,n) * A(n+1,2) * A(n+3,m)
    for (int i = 1; i <= n; i++)
        mul(a, i);
    mul(a, (n + 1) * n);
    for (int i = n + 3; i >= n + 3 - m + 1; i--)
        mul(a, i);
    // A(n,n) * A(n+1,1) * A(2,2) * A(m,1) * A(n+2,m-1)
    for (int i = 1; i <= n; i++)
        mul(b, i);
    mul(b, (n + 1) * 2 * m);
    for (int i = n + 2; i >= (n + 2) - (m - 1) + 1; i--)
        mul(b, i);
    // get ans
    add(a, b);
    for (int i = a.size() - 1; i >= 0; i--)
        cout << a[i];
    cout << "\n";
    return 0;
}

/*
高精度时能排列就别组合，毕竟排列数可以只涉及乘法，没有除法

老师中间有男生：男生排好后挑两个空位放老师，然后再在空位里放女生
A(n,n) * A(n+1,2) * A(n+3,m)

老师中间没男生：两老师+一女生打包
A(n,n) * A(n+1,1) * A(2,2) * A(m,1) * A(n+2,m-1)
*/

使用高精度模板

#include <bits/stdc++.h>
using namespace std;

struct BigIntTiny
{
    int sign;
    std::vector<int> v;

    BigIntTiny() : sign(1) {}
    BigIntTiny(const std::string &s) { *this = s; }
    BigIntTiny(int v)
    {
        char buf[21];
        sprintf(buf, "%d", v);
        *this = buf;
    }
    void zip(int unzip)
    {
        if (unzip == 0)
        {
            for (int i = 0; i < (int)v.size(); i++)
                v[i] = get_pos(i * 4) + get_pos(i * 4 + 1) * 10 + get_pos(i * 4 + 2) * 100 + get_pos(i * 4 + 3) * 1000;
        }
        else
            for (int i = (v.resize(v.size() * 4), (int)v.size() - 1), a; i >= 0; i--)
                a = (i % 4 >= 2) ? v[i / 4] / 100 : v[i / 4] % 100, v[i] = (i & 1) ? a / 10 : a % 10;
        setsign(1, 1);
    }
    int get_pos(unsigned pos) const { return pos >= v.size() ? 0 : v[pos]; }
    BigIntTiny &setsign(int newsign, int rev)
    {
        for (int i = (int)v.size() - 1; i > 0 && v[i] == 0; i--)
            v.erase(v.begin() + i);
        sign = (v.size() == 0 || (v.size() == 1 && v[0] == 0)) ? 1 : (rev ? newsign * sign : newsign);
        return *this;
    }
    std::string to_str() const
    {
        BigIntTiny b = *this;
        std::string s;
        for (int i = (b.zip(1), 0); i < (int)b.v.size(); ++i)
            s += char(*(b.v.rbegin() + i) + '0');
        return (sign < 0 ? "-" : "") + (s.empty() ? std::string("0") : s);
    }
    bool absless(const BigIntTiny &b) const
    {
        if (v.size() != b.v.size())
            return v.size() < b.v.size();
        for (int i = (int)v.size() - 1; i >= 0; i--)
            if (v[i] != b.v[i])
                return v[i] < b.v[i];
        return false;
    }
    BigIntTiny operator-() const
    {
        BigIntTiny c = *this;
        c.sign = (v.size() > 1 || v[0]) ? -c.sign : 1;
        return c;
    }
    BigIntTiny &operator=(const std::string &s)
    {
        if (s[0] == '-')
            *this = s.substr(1);
        else
        {
            for (int i = (v.clear(), 0); i < (int)s.size(); ++i)
                v.push_back(*(s.rbegin() + i) - '0');
            zip(0);
        }
        return setsign(s[0] == '-' ? -1 : 1, sign = 1);
    }
    bool operator<(const BigIntTiny &b) const
    {
        return sign != b.sign ? sign < b.sign : (sign == 1 ? absless(b) : b.absless(*this));
    }
    bool operator==(const BigIntTiny &b) const { return v == b.v && sign == b.sign; }
    BigIntTiny &operator+=(const BigIntTiny &b)
    {
        if (sign != b.sign)
            return *this = (*this) - -b;
        v.resize(std::max(v.size(), b.v.size()) + 1);
        for (int i = 0, carry = 0; i < (int)b.v.size() || carry; i++)
        {
            carry += v[i] + b.get_pos(i);
            v[i] = carry % 10000, carry /= 10000;
        }
        return setsign(sign, 0);
    }
    BigIntTiny operator+(const BigIntTiny &b) const
    {
        BigIntTiny c = *this;
        return c += b;
    }
    void add_mul(const BigIntTiny &b, int mul)
    {
        v.resize(std::max(v.size(), b.v.size()) + 2);
        for (int i = 0, carry = 0; i < (int)b.v.size() || carry; i++)
        {
            carry += v[i] + b.get_pos(i) * mul;
            v[i] = carry % 10000, carry /= 10000;
        }
    }
    BigIntTiny operator-(const BigIntTiny &b) const
    {
        if (sign != b.sign)
            return (*this) + -b;
        if (absless(b))
            return -(b - *this);
        BigIntTiny c;
        for (int i = 0, borrow = 0; i < (int)v.size(); i++)
        {
            borrow += v[i] - b.get_pos(i);
            c.v.push_back(borrow);
            c.v.back() -= 10000 * (borrow >>= 31);
        }
        return c.setsign(sign, 0);
    }
    BigIntTiny operator*(const BigIntTiny &b) const
    {
        if (b < *this)
            return b * *this;
        BigIntTiny c, d = b;
        for (int i = 0; i < (int)v.size(); i++, d.v.insert(d.v.begin(), 0))
            c.add_mul(d, v[i]);
        return c.setsign(sign * b.sign, 0);
    }
    BigIntTiny operator/(const BigIntTiny &b) const
    {
        BigIntTiny c, d;
        d.v.resize(v.size());
        double db = 1.0 / (b.v.back() + (b.get_pos((unsigned)b.v.size() - 2) / 1e4) +
                           (b.get_pos((unsigned)b.v.size() - 3) + 1) / 1e8);
        for (int i = (int)v.size() - 1; i >= 0; i--)
        {
            c.v.insert(c.v.begin(), v[i]);
            int m = (int)((c.get_pos((int)b.v.size()) * 10000 + c.get_pos((int)b.v.size() - 1)) * db);
            c = c - b * m, d.v[i] += m;
            while (!(c < b))
                c = c - b, d.v[i] += 1;
        }
        return d.setsign(sign * b.sign, 0);
    }
    BigIntTiny operator%(const BigIntTiny &b) const { return *this - *this / b * b; }
    bool operator>(const BigIntTiny &b) const { return b < *this; }
    bool operator<=(const BigIntTiny &b) const { return !(b < *this); }
    bool operator>=(const BigIntTiny &b) const { return !(*this < b); }
    bool operator!=(const BigIntTiny &b) const { return !(*this == b); }
};

int n, m;
BigIntTiny ans1, ans2, ans;
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m;
    // A(n,n) * A(n+1,2) * A(n+3,m)
    ans1 = 1;
    for (int i = 1; i <= n; i++)
        ans1 = ans1 * i;
    ans1 = ans1 * ((n + 1) * n);
    for (int i = n + 3; i >= n + 3 - m + 1; i--)
        ans1 = ans1 * i;
    // cout << ans1.to_str() << "\n";
    // A(n,n) * A(n+1,1) * A(2,2) * A(m,1) * A(n+2,m-1)
    ans2 = 1;
    for (int i = 1; i <= n; i++)
        ans2 = ans2 * i;
    ans2 = ans2 * ((n + 1) * 2 * m);
    for (int i = n + 2; i >= (n + 2) - (m - 1) + 1; i--)
        ans2 = ans2 * i;
    // cout << ans2.to_str() << "\n";
    // get ans
    ans1 += ans2;
    cout << ans1.to_str() << "\n";
    return 0;
}

/*
高精度时能排列就别组合，毕竟排列数可以只涉及乘法，没有除法

老师中间有男生：男生排好后挑两个空位放老师，然后再在空位里放女生
A(n,n) * A(n+1,2) * A(n+3,m)

老师中间没男生：两老师+一女生打包
A(n,n) * A(n+1,1) * A(2,2) * A(m,1) * A(n+2,m-1)
*/