【模板】【数论】高精度

#include 
#include 
#include 
#include 
#include 
#include 

#define re register

using namespace std;

const int MAXN = 10003;
const int base = 10000;

struct Bigint{
    int num[MAXN];
    int len,sign;
    Bigint() {memset(num,0,sizeof(num)); len=1; sign=1;}

    Bigint operator = (const char *s) 
    {
        int l=strlen(s);
        int k=1;
        len=1;
        for(re int i=1;i<=l;i++)
        {
            if(k==base) k=1,++len;
            num[len]+=(s[l-i]-'0')*k;
            k=k*10;
        }       
        return *this;
    }

    Bigint operator = (const int &x)
    {
        char s[MAXN];
        sprintf(s,"%d",x);
        *this=s;
        return *this;
    }

    bool operator < (const Bigint &x) const
    {
        bool flag=0;
        if(sign==-1&&x.sign==1) return true;
        if(sign==1&&x.sign==-1) return false;
        if(sign==-1&&x.sign==-1) flag=1;        
        if(len!=x.len) return lenfor(re int i=len;i>=1;i--) 
            if(num[i]!=x.num[i]) return flag?x.num[i]return false;
    }

    bool operator > (const Bigint &x) const {return x<*this;}
    bool operator <= (const Bigint &x) const {return !(*this>x);}
    bool operator >= (const Bigint &x) const {return !(*thisbool operator == (const Bigint &x) const {return !(*thisthis>x);}
    bool operator != (const Bigint &x) const {return !(*this==x);}

    Bigint operator + (const Bigint &b) const
    {
        Bigint c;
        c.len=max(len,b.len);
        for(re int i=1;i<=c.len;i++)
        {
            c.num[i]+=num[i]+b.num[i];
            if(c.num[i]>=base) c.num[i]-=base,++c.num[i+1];
        }
        if(c.num[c.len+1]) ++c.len;
        return c;
    }

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

    Bigint operator + (const int &x)
    {
        Bigint b;
        b=x;
        return *this+b;
    }

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

    Bigint operator ++ (int b)
    {
        return *this+=1;
    }

    Bigint operator - (const Bigint &x) const//一定要加const！因为有swap操作！ 
    {
        Bigint a,b,c;
        a=*this;b=x;
        c.len=max(a.len,b.len);
        if(*this1;
        for(re int i=1;i<=c.len;i++)
        {
            c.num[i]+=a.num[i]-b.num[i];
            if(c.num[i]<0) c.num[i]+=base,--c.num[i+1];
        }
        while(!c.num[c.len]&&c.len>1) --c.len;
        return c;
    }

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

    Bigint operator - (const int &x)
    {
        Bigint b;
        b=x;
        return *this-b;
    }

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

    Bigint operator -- (int b)
    {
        return *this-=1;
    }

    Bigint operator * (const int &b) const
    {
        Bigint c;
        c.len=len+1;
        for(re int i=1;i<=len;i++)
        {
            c.num[i]+=num[i]*b;
            c.num[i+1]=c.num[i]/base;
            c.num[i]%=base;
        }
        while(!c.num[c.len]&&c.len>1) --c.len;
        return c;
    }

    Bigint operator * (const Bigint &b) const
    {
        Bigint c;
        if(*this+b==*this||*this+b==b) return c;
        c.len=len+b.len;
        for(re int i=1;i<=len;i++)
            for(re int j=1;j<=b.len;j++)
            {
                c.num[i+j-1]+=num[i]*b.num[j];
                c.num[i+j]+=c.num[i+j-1]/base;
                c.num[i+j-1]%=base;
            }
        while(!c.num[c.len]&&c.len>1) --c.len;
        return c;
    }

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

    Bigint operator / (const int &b) const
    {
        Bigint c;
        c.len=len;
        int x=0;
        for(re int i=c.len;i>=1;i--)
        {
            c.num[i]+=(x*base+num[i])/b;
            x=(x*base+num[i])%b;
        }
        while(!c.num[c.len]&&c.len>1) --c.len;
        return c;
    }

    int operator % (const int &b) const
    {
        int ans=0;
        for(re int i=1;i<=len;i++) ans=(ans*10+num[i])%b;
        return ans;
    }

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

    Bigint Copy(const Bigint &a,int x)//从高位开始截取长度为x的子段 
    {
        Bigint t;
        t.len=a.len+x-1;
        for(int i=1;i<=a.len;i++) t.num[i+x-1]=a.num[i];
        while(!t.num[t.len]&&t.len>1) --t.len;
        return t;
    }

    //模拟竖式 高精除 
    Bigint Div1(const Bigint &a,const Bigint &b,Bigint &mod)
    {
        Bigint c;
        c.len=a.len-b.len+1;
        mod=a;
        for(int i=c.len;i>=1;i--)
        {
            Bigint t;
            t=Copy(b,i);
            while(mod>=t)
            {
                c.num[i]++;
                mod-=t;
            }
        }
        while(!c.num[c.len]&&c.len>0) --c.len;
        return c;
    }


    //倍增 模拟竖式 高精除 
    Bigint Div2(const Bigint &a,const Bigint &b,Bigint &mod)
    {
        Bigint c;
        c.len=a.len-b.len+1;
        mod=a;
        int pw[20]; pw[0]=1;
        for(int i=1;i<=15;i++) pw[i]=pw[i-1]<<1;//预处理倍增数组(2^k)
        for(int i=c.len;i>=1;i--)
        {
            Bigint t;
            t=Copy(b,i);
            for(int j=15;j>=0;j--)
                if(mod>=t*pw[j])
                {
                    c.num[i]+=pw[j];
                    mod-=t*pw[j];
                }
        }
        while(!c.num[c.len]&&c.len>1) --c.len;
        return c;
    }

    Bigint operator / (const Bigint &b)
    {
        Bigint c;
        if(*thisreturn c;
        return Div2(*this,b,c);
    }

    Bigint operator % (const Bigint &b) 
    {
        if(*thisreturn *this;
        Bigint c;
        Div2(*this,b,c);
        return c;
    }

    /*
    //二分高精除，基于高精乘，高精除单精 O(len^2*loglen) 
    Bigint operator / (const Bigint &b)
    {
        Bigint l,r,mid;
        if(*this*this) l--;
        return l;
    }

    Bigint operator % (const Bigint &b)
    {
        return *this-(*this/b)*b;
    }
    */

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

    inline void read()
    {
        char s[MAXN];
        scanf("%s",s);
        *this=s;
    }

    inline void write()
    {
        if(sign==-1) putchar('-');
        printf("%d",num[len]);
        for(re int i=len-1;i>=1;i--) printf("%04d",num[i]);
        putchar('\n');
    }

};

Bigint a,b;

int main()
{
    a.read();
    b.read();
    (a+b).write();
    (a-b).write();
    (a*b).write();
    (a/b).write();
    (a%b).write();
    return 0;
}