完全正负大数模板（正负数加减乘除求模运算）~~~~~

原模板是从kuangbin的acm模板里copy过来的，根据博主的代码风格对于模板做了一些写法上的小调整，不过呢~

因为博主本人有强迫症（ACMer通病）~~~所以经过一个下午+晚上的修改，将原来只支持无符号大整数的运算改成了支持有符号大整数的运算~~乘法除法挺好修改的，对于新的加法减法写了两个只支持无符号大数的加减法，根据运算符两边的符号位决定运算方式~~~顺便加上了大整数之间的除法运算和几个比较运算符~

模板检查了些许遍，应该没有啥bug了，除了输入-0(本来就不应该吗~)~~~~(有发现的童鞋一定要戳我~~~)

检验状况：

附上模板吧

//Copy from kuangbin~,modify by Siryuanshao
#include 
#include 
#include 
#include 
#include 
#define MAXN 999999999
#define MAXSIZE 5000
#define DLEN 9
using namespace std;
class BigInt
{
    private:
        int a[500];
        int len;
        bool sign;
        //sign表示符号位的正负~
    protected:
        BigInt add(const BigInt&,const bool)const;
        BigInt subtract(const BigInt&,const bool)const;
         //两个无符号整形的加减法,flag标明结果的符号位~~
    public:
        BigInt() {sign=false;len=1;memset(a,0,sizeof(a));}
        BigInt(const int);
        BigInt(const char*);
        BigInt(const BigInt&);
        BigInt& operator=(const BigInt&);
        friend istream& operator>>(istream&,BigInt&);
        friend ostream& operator<<(ostream&,const BigInt&);
        friend BigInt abs(const BigInt&);

        BigInt operator+(const BigInt&)const;
        BigInt operator-(const BigInt&)const;
        BigInt operator*(const BigInt&)const;
        BigInt operator/(const BigInt&)const;
        BigInt operator/(const int&)const;

        BigInt operator^(const int&)const;
        int operator%(const int&)const;
        bool operator<(const BigInt&)const;
        bool operator>(const BigInt&)const;
        bool operator<=(const BigInt&)const;
        bool operator>=(const BigInt&)const;
        bool operator==(const BigInt&)const;

        inline int size() {return DLEN*(len-1)+to_string(a[len-1]).size();}
};
//对于负数的处理~~~
BigInt::BigInt(const int b)
{
    int c,d=abs(b);
    len=0;
    sign=b<0;
    memset(a,0,sizeof(a));
    while(d>MAXN)
    {
        c=d-(d/(MAXN+1))*(MAXN+1);
        d=d/(MAXN+1);
        a[len++]=c;
    }
    a[len++]=d;
}
BigInt::BigInt(const char *in)
{
    const char *s;
    if(in[0]=='-') s=in+1,sign=true;
    else s=in,sign=false;
    int t,k,index,L,i;
    memset(a,0,sizeof(a));
    L=strlen(s);
    len=L/DLEN;
    if(L%DLEN) len++;
    index=0;
    for(i=L-1;i>=0;i-=DLEN)
    {
        t=0;
        k=i-DLEN+1;
        if(k<0) k=0;
        for(int j=k;j<=i;j++)
            t=t*10+s[j]-'0';
        a[index++]=t;
    }
}
BigInt::BigInt(const BigInt& T):len(T.len),sign(T.sign)
{
    memset(a,0,sizeof(a));
    for(int i=0;i>(istream& in,BigInt& b)
{
    char ch[MAXSIZE];
    in>>ch;
    b=BigInt(ch);
    return in;
}
ostream& operator<<(ostream& out,const BigInt& b)
{
    out<<(b.sign?"-":"")<=0;i--) out<len?T.len:len;
    for(int i=0;iMAXN)
        {
            t.a[i+1]++;
            t.a[i]-=MAXN+1;
        }
    }
    if(t.a[big]!=0) t.len=big+1;
    else t.len=big;
    return t;
}
BigInt BigInt::subtract(const BigInt& T,const bool flag)const
{
    BigInt t(*this);
    t.sign=flag;
    for(int i=0;ii) t.a[j--]+=MAXN;
            t.a[i]+=MAXN+1-T.a[i];
        }
        else t.a[i]-=T.a[i];
    }
    while(t.a[t.len-1]==0&&t.len>1) t.len--;
    return t;
}
BigInt BigInt::operator+(const BigInt& T)const
{
    BigInt ret;
    if(sign^T.sign)
    {
        BigInt t1(*this),t2(T);
        if(abs(t1)add(T,sign);
    return ret;
}
BigInt BigInt::operator-(const BigInt& T)const
{
    BigInt ret;
    if(sign^T.sign) ret=this->add(T,sign);
    else
    {
        BigInt t1(*this),t2(T);
        bool sn;
        if(abs(t1)MAXN)
            {
                temp1=temp%(MAXN+1);
                up=temp/(MAXN+1);
                ret.a[i+j]=temp1;
            }
            else
            {
                up=0;
                ret.a[i+j]=temp;
            }
        }
        if(up!=0) ret.a[i+T.len]=up;
    }
    ret.sign=sign^T.sign;
    ret.len=len+T.len;
    while(ret.a[ret.len-1]==0&&ret.len>1) ret.len--;
    return ret;
}
BigInt BigInt::operator/(const BigInt& T)const
{
    BigInt r(*this),ret(0);
    while(r>=T)
    {
        BigInt down(1);
        while(r-T*down>=0) down=down*10;
        down=down/10;
        r=r-T*down;
        ret=ret+down;
    }
    ret.sign=sign^T.sign;
    return ret;
}
BigInt BigInt::operator/(const int &b)const
{
    BigInt ret;
    bool sign1=b<0;
    long long down=0;
    for(int i=len-1;i>=0;i--)
    {
        ret.a[i]=(a[i]+down*(MAXN+1))/b;
        down=a[i]+down*(MAXN+1)-(long long)ret.a[i]*b;
    }
    ret.sign=sign^sign1;
    ret.len=len;
    while(ret.a[ret.len-1]==0&&ret.len>1) ret.len--;
    return ret;
}
int BigInt::operator%(const int &b)const
{
    int d=0;
    for(int i=len-1;i>=0;i--)
        d=(((long long)d*(MAXN+1))%b+a[i])%b;
    return sign?-d:d;
}
BigInt BigInt::operator^(const int &n)const
{
    BigInt ret(1),t(*this);
    int m=n;
    while(m)
    {
        if(m&1) ret=ret*t;
        t=t*t;
        m>>=1;
    }
    return ret;
}
bool BigInt::operator<(const BigInt& T)const
{
    if(sign&&!T.sign) return true;
    if(!sign&&T.sign) return false;
    //只有sign相同才能作比较~~
    if(len!=T.len) return sign^(len=0;ln--)
        if(a[ln]!=T.a[ln]) return sign^(a[ln](const BigInt& T)const
{
    return T<*this;
}
bool BigInt::operator<=(const BigInt& T)const
{
    if(*this==T) return true;
    return *this=(const BigInt& T)const
{
    return T<=*this;
}
bool BigInt::operator==(const BigInt& T)const
{
    if(sign!=T.sign||len!=T.len) return false;
    for(int i=len-1;i>=0;i--)
        if(a[i]!=T.a[i]) return false;
    return true;
}