大數模板

用了交大的模板，增加了base進制，有個地方要注意的是，base 不能開太大，因爲在做加法或者乘法的時候，有可能就發生溢出了，如果是開int數組，那最好base = 10^5,

還有，maxn也不能開太大，否則會出錯，下面模板base = 10^5，maxn開10^6次方爆掉還不知道什麼原因

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

struct Hp_integer
{
    static const int base = 100000;
    static const int width = 5;//base後有width個０
    static const int maxn = 100000;

    int num[maxn], cnt;
    char s3[maxn];

    void init()
    {
        cnt = 0;
        memset(num, 0, sizeof(num));
    }

    void print()
    {
        if (cnt == 0)
        {
            printf("0\n");
            return;
        }
        for (int i = cnt - 1; i >= 0; i--)
        {
            if (i == cnt - 1)
                printf("%d", num[i]);
            else
                printf("%05d", num[i]);
        }
        printf("\n");
    }

    int comp(const Hp_integer &b)
    {
        if (cnt > b.cnt) return 1;
        if (cnt < b.cnt) return -1;
        int i = cnt - 1;
        while (i > 0 && num[i] == b.num[i]) i--;
        return num[i] - b.num[i];
    }

    bool operator > (const Hp_integer &b)
    {
        return this->comp(b) > 0;
    }

    bool operator >= (const Hp_integer &b)
    {
        return this->comp(b) >= 0;
    }

    bool operator < (const Hp_integer &b)
    {
        return this->comp(b) < 0;
    }

    bool operator <= (const Hp_integer &b)
    {
        return this->comp(b) <= 0;
    }

    bool operator == (const Hp_integer &b)
    {
        return this->comp(b) == 0;
    }

    bool operator != (const Hp_integer &b)
    {
        return this->comp(b) != 0;
    }

    Hp_integer operator = (const Hp_integer &b)
    {
        cnt = b.cnt;
        for (int i = 0; i < b.cnt; i++)
            num[i] = b.num[i];
        return (*this);
    }

    Hp_integer operator = (const char *s)
    {
        int len = strlen(s), x;
        int l = (len - 1) / width + 1;
        cnt = 0;
        for (int i = 0; i < l; i++)
        {
            int end = len - i * width;
            int start = max(0, end - width);
            strncpy(s3, s + start, end - start);
            s3[end - start] = '\0';
            sscanf(s3, "%d", &x);
            num[cnt++] = x;
        }
        return (*this);
    }

    Hp_integer operator + (const Hp_integer &b)
    {
        Hp_integer c;
        c.init();
        for (int i = 0; i < cnt || i < b.cnt; i++)
        {
            if (i < cnt) c.num[i] += num[i];
            if (i < b.cnt) c.num[i] += b.num[i];
            c.num[i + 1] = c.num[i] / base;
            c.num[i] %= base;
        }
        c.cnt = max(cnt, b.cnt) + 1;
        while (c.cnt > 1 && c.num[c.cnt - 1] == 0) c.cnt--;
        return c;
    }

    Hp_integer operator += (const Hp_integer &b)
    {
        (*this) = (*this) + b;
        return (*this);
    }

    Hp_integer operator - (const Hp_integer &b)
    {
        Hp_integer c;
        c.init();
        for (int i = 0, j = 0, g = 0; i < cnt; i++, j++)
        {
            int x = -g;
            if (i < cnt) x += num[i];
            if (i < b.cnt) x -= b.num[i];
            if (x >= 0) g = 0;
            else
            {
                g = 1;
                x += base;
            }
            c.num[c.cnt++] = x;
        }
        while (c.cnt > 1 && c.num[c.cnt - 1] == 0) c.cnt--;
        return c;
    }

    Hp_integer operator -=(const Hp_integer &b)
    {
        (*this) = (*this) - b;
        return (*this);
    }

    Hp_integer operator * (const Hp_integer &b) const
    {
        Hp_integer c;
        c.init();
        for (int i = 0; i < cnt; i++)
        {
            for (int j = 0; j < b.cnt; j++)
            {
                c.num[i + j] += num[i] * b.num[j];
                c.num[i + j + 1] += c.num[i + j] / base;
                c.num[i + j] %= base;
            }
        }
        c.cnt = cnt + b.cnt;
        while (c.cnt > 1 && c.num[c.cnt - 1] == 0) c.cnt--;
        return c;
    }

    Hp_integer operator *= (const Hp_integer &b)
    {
        (*this) = (*this) * b;
        return (*this);
    }

    Hp_integer operator / (const Hp_integer &b)
    {
        Hp_integer c, d;
        c.init(), d.init();
        if (b.cnt == 1 && b.num[0] == 0) return c;
        for (int i = cnt - 1; i >= 0; i--)
        {
            if (d.cnt != 1 || d.num[0] != 0)
            {
                for (int j = d.cnt; j > 0; j--)
                    d.num[j] = d.num[j - 1];
                d.cnt++;
            }
            d.num[0] = num[i];
            c.num[i] = 0;
            while (d >= b)
            {
                d -= b;
                c.num[i]++;
            }
        }
        c.cnt = cnt;
        while (c.cnt > 1 && c.num[c.cnt - 1] == 0) c.cnt--;
        return c;
    }

    Hp_integer operator /= (const Hp_integer &b)
    {
        (*this) = (*this) / b;
        return (*this);
    }

    Hp_integer operator % (const Hp_integer &b)
    {
        Hp_integer c;
        c.init();
        if (b.cnt == 1 && b.num[0] == 0) return c;
        for (int i = cnt - 1; i >= 0; i--)
        {
            if (c.cnt != 1 || c.num[0] != 0)
            {
                for (int j = c.cnt; i > 0; i--)
                    c.num[j] = c.num[j - 1];
                c.cnt++;
            }
            c.num[0] = num[i];
            while (c >= b) c -= b;
        }
        return c;
    }

    Hp_integer operator %= (const Hp_integer &b)
    {
        (*this) = (*this) % b;
        return (*this);
    }
};

int main()
{
    char s1[10000], s2[10000];
    while (true)
    {
        Hp_integer a, b, c;
        a.init();
        b.init();
        c.init();
        scanf("%s%s", s1, s2);

        a = s1, b = s2;

        //c = a + b;
        //c.print();

        //c = a - b;
        //c.print();

        //c = a * b;
        //c.print();

        //c = a / b;
        //c.print();

        //c = a % b;
        //c.print();
    }
    return 0;
}