__int128的实现

Posted 2020-10-23 baka

#include<bitset>  
#include<algorithm>  
#include<iostream>  
#include<string>  
#include<deque>  
#include<cstdio>
using namespace std;  
  
class int128;  
  
void shift(int128 & in,deque<bool> & de);  
  
template<size_t N>  
bool operator<(bitset<N> const& b1,bitset<N> const& b2)  
{  
    int i=N;  
    while( i-- && b1[i]==b2[i] ) { }  
  
    return ((-1 == i) ? false : (b1[i]<b2[i]));  
}  
  
class int128  
{  
    bitset<128> number;  
public:  
    explicit int128(string str):number(str){}  
    int128(bitset<128>const& b):number(b){}  
    int128(int a = 0 , int b = 0 , int c = 0 , int d = 0)  
    {  
        bitset<32> b1(a),b2(b),b3(c),b4(d);  
        int i, k = 128;  
        for(i = 32 ; i ; number[--k] = b1[--i]) { }  
        for(i = 32 ; i ; number[--k] = b2[--i]) { }  
        for(i = 32 ; i ; number[--k] = b3[--i]) { }  
        for(i = 32 ; i ; number[--k] = b4[--i]) { }  
    }  
    bool operator[](size_t i)const  
    {  
        return number[i];  
    }  
    bitset<128>::reference operator[](size_t i)  
    {  
        return number[i];  
    }  
    friend bool operator<(int128 const& i1,int128 const& i2)  
    {  
        return i1.number < i2.number;  
    }  
  
    friend int128 operator+(int128 const& i1,int128 const& i2)  
    {  
        if(i1 == 0)  
            return i2;  
        if(i2 == 0)  
            return i1;  
        int128 result;  
        bitset<2> sum;  
  
        for(int i = 0 ; i < 128 ; ++i)  
        {  
            sum=i1[i]+i2[i]+sum.to_ulong();  
            result[i]=sum[0];  
            sum>>=1;  
        }  
        return result;  
    }  
  
    friend int128 operator-(int128 const& i1,int128 const& i2)  
    {  
        if(i2==0)  
            return i1;  
  
        int128 result=i1;  
  
        for(int i = 0 ; i < 128 ; ++i)  
        {  
            if(i2[i] == 0)   {}  
            else  
            {  
                if(result[i] == 1)  
                    result[i] = 0;  
                else  
                {  
                    int k = i;  
                    while(k < 128 && result[k] == 0)  
                    {  
                        result[k] = 1;  
                        ++k;  
                    }  
                    if(k != 128)  
                        result[k] = 0;  
                }  
            }  
        }  
  
        return result;  
    }  
    friend int128 operator*(int128 const& i1,int128 const& i2)  
    {  
        if(i1==0 || i2==0)  
            return int128();  
        if(i1==1)  
            return i2;  
        if(i2==1)  
            return i1;  
  
        int128 acc=int128();  
  
        for(int i=0;i<128;++i)  
        {  
            if(i2[i]==1)  
            {  
                acc=acc+(i1<<i);  
            }  
        }  
  
        return acc;  
    }  
    friend int128 operator/(int128 const& i1,int128 const& i2)  
    {  
        if(i1 < i2)  
            return int128();  
        deque<bool> de;  
        bool flag = 0;  
        for(int i = 127 ; i >= 0 ; --i)  
        {  
            if(flag == 0 && i1[i] == 0)   {}  
            else  
            {  
                flag = 1;  
                de.push_back(i1[i]);  
            }  
        }  
  
        int128 div = int128();  
        int128 result = int128();  
  
        while(!de.empty())  
        {  
            shift(div,de);  
            if(div < i2)  
            {  
                result = result<<1;  
            }  
            else  
            {  
                result = (result<<1) + int128(0,0,0,1);  
                div = div - i2;  
            }  
        }  
  
        return result;  
    }  
    friend int128 operator%(int128 const& i1,int128 const& i2)  
    {  
        if(i1 < i2)  
            return i1;  
        deque<bool> de;  
        bool flag = 0;  
        for(int i = 127 ; i >= 0 ; --i)  
        {  
            if(flag == 0 && i1[i] == 0)   {}  
            else  
            {  
                flag = 1;  
                de.push_back(i1[i]);  
            }  
        }  
  
        int128 div = int128();  
        int128 result = int128();  
  
        while(!de.empty())  
        {  
            shift(div,de);  
            if(div < i2)  
            {  
                result = result<<1;  
            }  
            else  
            {  
                result = (result<<1) + int128(0,0,0,1);  
                div = div - i2;  
            }  
        }  
  
        return div;  
    }  
    friend bool operator==(int128 const& i,int const k)  
    {  
        bitset<32> bb(k);  
        for(int g = 0 ; g < 32 ; ++g)  
        {  
            if(i[g] != bb[g])  
                return 0;  
        }  
        return 1;  
    }  
    void operator=(bitset<128>const& b)  
    {  
        number = b;  
    }  
    friend ostream& operator<<(ostream& o,int128 const& i)  
    {  
        o<<i.number;  
        return o;  
    }  
    int128 operator<<(size_t step)const  
    {  
        return int128(number<<step);  
    }  
    unsigned long to_ulong()const  
    {  
        return *((unsigned long*)&number);  
    }  
  
public:  
    bool ToDecimalStr(std::string &str)  
    {  
        str.clear();  
        char buf[128] = {0};  
        int128 Radix(0, 0, 0, 10);  
        for(int128 num = number; !(num == 0); num = num/Radix)  
        {  
            if( sprintf(buf, "%d", ((int)(num%Radix).to_ulong())) < 0 )  
            {  
                return false;  
            }  
            str = buf + str;  
        }  
        return true;  
    }  
  
    static void Print(int128 & data, bool bEndl = true)  
    {  
        string str;  
        if( data.ToDecimalStr(str) )  
        {  
            printf("%s%s", str.c_str(), (bEndl?"\n":""));  
        }  
    }  
};  
  
static int128 const one = int128(0,0,0,1);  
  
template<size_t N>  
void add_one(bitset<N>& b)  
{  
    int i = 0;  
    while(i < N && b[i] == 1)  
    {  
        b[i] = 0;  
        ++i;  
    }  
    if(i == N)  
        return;  
    b[i] = 1;  
}  
  
void add_one(int128& k)  
{  
    int i = 0;  
    while(i < 128 && k[i] == 1)  
    {  
        k[i] = 0;  
        ++i;  
    }  
    if(i == 128)  
        return;  
    k[i] = 1;  
}  
  
void shift(int128 & in,deque<bool> & de)  
{  
    if(de.front()==1)  
    {  
        de.pop_front();  
        in=(in<<1)+one;  
    }  
    else  
    {  
        de.pop_front();  
        in=in<<1;  
    }  
}  
  
bool IsPrime(int128 const& number)  
{  
    for(int128 i = int128(0,0,0,2) ; i < number ; add_one(i))  
    {  
        if(number%i == 0)  
            return 0;  
    }  
    return 1;  
}

　　这个是某dalao写的int128类，可能不是那么好用，暂存，回家搞一点事情。