大数模板

bignum.cpp

#define MAXN 9999
#define DLEN 4
class BigNum {
private:
    int a[1000];//可以控制大数的位数
    int len; //大数长度
public:
    BigNum() {len = 1;memset(a,0,sizeof(a));}
    BigNum(const int);
    BigNum(const char*);
    BigNum(const BigNum &);
    BigNum &operator=(const BigNum &);
    BigNum operator+(const BigNum &) const;
    BigNum operator-(const BigNum &) const;
    BigNum operator*(const BigNum &) const;
    BigNum operator/(const int   &) const;
    BigNum operator^(const int   &) const;
    int   operator%(const int   &) const;
    bool   operator>(const BigNum & T)const;
    void print();
};

BigNum::BigNum(const int b) {
    int c,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) {
    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;
    }
}
BigNum::BigNum(const BigNum & T) : len(T.len) {
    int i;
    memset(a,0,sizeof(a));
    for(i = 0 ; i < len ; i++)a[i] = T.a[i];
}
BigNum & BigNum::operator=(const BigNum & n) {
    len = n.len;
    memset(a,0,sizeof(a));
    int i;
    for(i = 0 ; i < len ; i++)
        a[i] = n.a[i];
    return *this;
}
BigNum BigNum::operator+(const BigNum & T) const {
    BigNum t(*this);
    int i,big;//位数
    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 {
    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 {
    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 {
    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 {
    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 {
    BigNum t,ret(1);
    if(n<0)exit(-1);
    if(n==0)return 1;
    if(n==1)return *this;
    int m=n;
    while(m>1) {
        t=*this;
		int i;
        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 {
    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;
        else return false;
    } else return false;
}
void BigNum::print() {
    int i;
    cout << a[len - 1];
    for(i = len - 2 ; i >= 0 ; i--) {
        cout.width(DLEN);
        cout.fill('0');
        cout << a[i];
    }
}
//读取整数
const int ok = 1;
int get_val(int & ret) {
    ret = 0;
    char ch;
    while ((ch=getchar()) > '9' || ch < '0') ;
    do {
        ret = ret*10 + ch - '0';
    } while ((ch=getchar()) <= '9' && ch >= '0') ;
    return ok;
}

//带负数
int get_val(int & ret) {
    ret = 0;
    char ch;
	bool neg = false;
    while (((ch=getchar()) > '9' || ch < '0') && ch!='-') ;
	if (ch == '-') {
		neg = true;
		while ((ch=getchar()) > '9' || ch < '0') ;
	}
    do {
        ret = ret*10 + ch - '0';
    } while ((ch=getchar()) <= '9' && ch >= '0') ;
	ret = (neg? -ret : ret);
	return ok;
}

//读取整数,可判EOF和EOL
const int eof = -1;
const int eol = -2;
int get_val(int & ret) {
    ret = 0;
    char ch;
    while (((ch=getchar()) > '9' || ch < '0') && ch!=EOF) ;
	if (ch == EOF) return eof;
    do {
        ret = ret*10 + ch - '0';
    } while ((ch=getchar()) <= '9' && ch >= '0') ;
	if (ch == '\n') return eol;
    return ok;
}

//读取浮点数
int get_val(double & ret) {
	ret = 0;
    double base = 0.1;
    char ch;
    bool dot = false, neg = false;
    while (((ch=getchar()) > '9' || ch < '0') && ch != '.' && ch != '-') ;
    if (ch == '-') {
        neg = true;
        while (((ch=getchar()) > '9' || ch < '0') && ch != '.' && ch != '-') ;
    }
    do {
        if (ch == '.') {
            dot = true;
            continue;
        }
        if (dot) {
            ret += (ch-'0') * base;
            base *= 0.1;
        } else ret = ret*10 + (ch-'0');
    } while (((ch=getchar()) <= '9' && ch >= '0') || ch == '.') ;
    ret = (neg? -ret : ret);
    return ok;
}

typedef long long LL;
//LL MultiMod(LL a, LL b, LL c) {
// if (b)
//  return (a * (b & 1) % c + (MultiMod(a, b >> 1, c) << 1)) % c;
// return 0;
//}

LL MultiMod(LL a, LL b, LL c) {
	LL ret = 0, d = a;
	for (; b; b >>= 1, d <<= 1, d %= c)
		if ((b & 1))
			ret = (ret + d) % c;
	return ret;
}

// 128-bits integer's power with mod in O(64*LogN)
LL ModPower(LL base, LL exp, LL mod) {
	LL ret = 1;
	for (; exp; exp >>= 1, base = MultiMod(base, base, mod))
		if ((exp & 1))
			ret = MultiMod(ret, base, mod);
	return ret;
}