大数的各种操作模板

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kunagbin 的板子
#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>#include <cmath>#include <vector>#include <queue>#include <map>#include <limits.h>using namespace std;typedef long long ll;#define MAXN 9999#define MAXSIZE 1010#define DLEN 4class BigNum{    int a[500];    int len;public:    BigNum()    {        len=1;        memset(a,0,sizeof(a));    };    BigNum(const int);  //将一个int类型的变量转换为大数    BigNum(const char*);   //将一个字符串类型的变量转换为大数    BigNum(const BigNum &); //拷贝构造函数    BigNum &operator=(const BigNum &);  //重载赋值运算符=，使得大数之间可以用=进行赋值    friend istream& operator>>(istream&,BigNum&);  //重载输入运算符    friend ostream& operator<<(ostream&,BigNum&);  //重载输出运算符    BigNum operator+(const BigNum &)const; //重载加法运算符，两个大数之间的相加运算    BigNum operator-(const BigNum &)const; //重载减法运算符，两个大数之间的相减运算    BigNum operator*(const BigNum &)const; //重载乘法运算符，两个大数之间的相乘运算    BigNum operator/(const int &)const; //重载除法运算符，两个大数之间的相除运算    BigNum operator^(const int &)const; //大数的n次方运算    int    operator%(const int &)const; //大数对一个int类型的数进行取模运算    bool   operator>(const BigNum &T)const; //大数和另一个大数的大小比较    bool   operator>(const int &t)const; //大数和一个int类型的数的大小比较    void print();//输出大数};BigNum::BigNum(const int b)//将一个int类型的变量转化为大数{    int c=0,d=b;    len=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;}BigNum::BigNum(const char *s)//将一个字符串类型的变量转换为大数{    int i,k,index,L;    memset(a,0,sizeof(a));    L=strlen(s);    len=L/DLEN;    if(L%DLEN)len++;    index=0;    for(i=L-1;i>=0;--i)    {        int 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;    }}BigNum::BigNum(const BigNum &T):len(T.len)//拷贝构造函数{    int i;    memset(a,0,sizeof(a));    for(i=0;i<len;i++)        a[i]=T.a[i];}BigNum &BigNum::operator=(const BigNum &n)//重载赋值运算符，大数之间复制运算{    int i;    len=n.len;    memset(a,0,sizeof(a));    for(i=0;i<len;i++)        a[i]=n.a[i];    return *this;}istream& operator>>(istream &in,BigNum &b){    char ch[MAXSIZE*4];    int i=1;    in>>ch;    int L=strlen(ch);    int count=0,sum=0;    for(i=L-1;i>=0;--i)    {        sum=0;        int t=1;        for(int j=0;j<4&&i>=0;j++,i--,t*=10)        {            sum+=(ch[i]-'0')*t;        }        b.a[count]=sum;        count++;    }    b.len=count++;    return in;}ostream& operator<<(ostream& out,BigNum& b)//重载输出操作符{    int i;    cout<<b.a[b.len-1];    for(i=b.len-2;i>=0;i--)        printf("%04d",b.a[i]);    return out;}BigNum BigNum::operator+(const BigNum &T)const //两个大数之间的相加运算{    BigNum t(*this);    int i,big;    big=T.len>len?T.len:len;    for(i=0;i<big;i++)    {        t.a[i]+=T.a[i];        if(t.a[i]>MAXN)        {            t.a[i+1]++;            t.a[i]-=MAXN+1;        }    }    if(t.a[big]!=0)        t.len=big+1;    else t.len=big;    return t;}BigNum BigNum::operator-(const BigNum &T)const //两个大数之间的相减运算{    int i,j,big;    bool flag;    BigNum t1,t2;    if(*this>T)    {        t1=*this;        t2=T;        flag=0;    }    else    {        t1=T;        t2=*this;        flag=1;    }    big=t1.len;    for(i=0;i<big;i++)    {        if(t1.a[i]<t2.a[i])        {            j=i+1;            while(t1.a[j]==0) j++;            t1.a[j--]--;            while(j>i)                t1.a[j--]+=MAXN;            t1.a[i]+=MAXN+1-t2.a[i];        }        else t1.a[i]-=t2.a[i];    }    t1.len=big;    while(t1.a[len-1]==0 && t1.len>1)    {        t1.len--;        big--;    }    if(flag)        t1.a[big-1]=0-t1.a[big-1];    return t1;}BigNum BigNum::operator*(const BigNum & T) const   //两个大数之间的相乘运算{BigNum ret;int i,j,up;int temp,temp1;for(i = 0 ; i < len ; i++){up = 0;for(j = 0 ; j < T.len ; j++){temp = a[i] * T.a[j] + ret.a[i + j] + up;if(temp > MAXN){temp1 = temp - temp / (MAXN + 1) * (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 + j] = up;}ret.len = i + j;while(ret.a[ret.len - 1] == 0 && ret.len > 1)ret.len--;return ret;}BigNum BigNum::operator/(const int& b) const   //大数间进行相除运算{BigNum ret;int i,down = 0;for(i = len - 1 ; i >= 0 ; i--){ret.a[i] = (a[i] + down * (MAXN + 1)) / b;down = a[i] + down * (MAXN + 1) - ret.a[i] * b;}ret.len = len;while(ret.a[ret.len - 1] == 0 && ret.len > 1)ret.len--;return ret;}int BigNum::operator%(const int & b) const    //大数对一个int类型的变量进行取模运算{int i,d=0;for (i = len-1; i>=0; i--){d = ((d * (MAXN+1))% b + a[i])% b;}return d;}BigNum BigNum::operator^(const int & n) const    //大数的n次方运算{BigNum t,ret(1);int i;if(n<0)exit(-1);if(n==0)return 1;if(n==1)return *this;int m=n;while(m>1){t=*this;for( i=1;i<<1<=m;i<<=1){t=t*t;}m-=i;ret=ret*t;if(m==1)ret=ret*(*this);}return ret;}bool BigNum::operator>(const BigNum & T) const   //大数和另一个大数的大小比较{int ln;if(len > T.len)return true;else if(len == T.len){ln = len - 1;while(a[ln] == T.a[ln] && ln >= 0)ln--;if(ln >= 0 && a[ln] > T.a[ln])return true;elsereturn false;}elsereturn false;}bool BigNum::operator >(const int & t) const    //大数和一个int类型的变量的大小比较{BigNum b(t);return *this>b;}void BigNum::print()    //输出大数{int i;printf("%d",a[len - 1]);for(i = len - 2 ; i >= 0 ; i--){printf("%04d",a[i]);}printf("\n");}BigNum dp[1808];int main(){    int n,k;    while(~scanf("%d%d",&n,&k))    {        dp[1]=k-1;        dp[2]=k*(k-1);        for(int i=3;i<=n;i++)            dp[i]=(BigNum)(k-1)*(dp[i-1]+dp[i-2]);        dp[n].print();    }    return 0;}
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