Wannafly Camp 2020 Day 1H 最大公约数

把每个质因子扒出来乱搞一下

#include <bits/stdc++.h>
using namespace std;
int g[505][505];
int isp[505];
struct Biguint {
	int a[10005], len;

	Biguint() {
		memset(a, 0, sizeof a);
		len = 0;
	}

	void read() {
		string str;
		cin >> str;
		memset(a, 0, sizeof a);
		len = str.length();
		for (int i = 0; i < str.size(); i++)
			a[i] = str[str.length() - i - 1] - '0';
	}

	void print() {
		for (int i = len - 1; i >= 0; i--) {
			cout << a[i];
		}
	}

	bool operator < (const Biguint& obj) {
		const int* b = obj.a;
		if (this->len == obj.len) {
			for (int i = 0; i < len; i++)
				if (a[i] != b[i]) return a[i] < b[i];
			return false;
		}
		else return this->len < obj.len;
	}

	bool operator > (const Biguint& obj) {
		const int* b = obj.a;
		if (this->len == obj.len) {
			for (int i = 0; i < len; i++)
				if (a[i] != b[i]) return a[i] > b[i];
			return false;
		}
		else return this->len > obj.len;
	}

	bool operator != (const Biguint& obj) {
		return (*this < obj) | (*this > obj);
	}

	bool operator == (const Biguint& obj) {
		return !((*this < obj) | (*this > obj));
	}

	bool operator <= (const Biguint& obj) {
		return (*this) < obj || (*this) == obj;
	}

	bool operator >= (const Biguint& obj) {
		return (*this) > obj || (*this) == obj;
	}

	Biguint operator += (const Biguint& obj) {
		const int* b = obj.a;
		if (obj.len > len) len = obj.len;
		for (int i = 0; i < len; i++) {
			a[i] += b[i];
			if (a[i] >= 10) a[i + 1] += a[i] / 10, a[i] %= 10;
		}
		if (a[len]) ++len;
		while (a[len - 1] >= 10)
			a[len] += a[len - 1] / 10, a[len - 1] %= 10, ++len;
		return *this;
	}

	Biguint operator + (const Biguint& obj) {
		Biguint ret;
		ret += *this;
		ret += obj;
		return ret;
	}

	Biguint operator -= (const Biguint& obj) {
		const int* b = obj.a;
		for (int i = 0; i < len; i++) {
			a[i] -= b[i];
			if (a[i] < 0) a[i + 1]--, a[i] += 10;
		}
		while (a[len - 1] == 0 && len > 0) --len;
		return *this;
	}

	Biguint operator -(const Biguint& obj) {
		Biguint ret;
		ret += *this;
		ret -= obj;
		return ret;
	}

	Biguint operator *= (int b) {
		for (int i = 0; i < len; i++)
			a[i] *= b;
		for (int i = 0; i < len; i++)
			a[i + 1] += a[i] / 10, a[i] %= 10;
		++len;
		while (a[len - 1] >= 10)
			a[len] += a[len - 1] / 10, a[len - 1] %= 10, ++len;
		while (a[len - 1] == 0 && len > 0) --len;
		return *this;
	}

	Biguint operator * (int b) {
		Biguint ret;
		ret = *this;
		ret *= b;
		return ret;
	}

	Biguint operator * (const Biguint& obj) {
		const int* b = obj.a;
		Biguint ret;
		for (int i = 0; i < len; i++)
			for (int j = 0; j < obj.len; j++)
				ret.a[i + j] += a[i] * b[j];
		for (int i = 0; i < len + obj.len; i++)
			ret.a[i + 1] += ret.a[i] / 10, ret.a[i] %= 10;
		ret.len = len + obj.len;
		++ret.len;
		while (ret.a[ret.len - 1])
			ret.a[ret.len] += ret.a[ret.len - 1] / 10, ret.a[ret.len - 1] %= 10, ++ret.len;
		while (ret.a[ret.len - 1] == 0 && ret.len > 0) --ret.len;
		return ret;
	}

};
ostream& operator << (ostream& os, Biguint num)
{
	//cout << "[" << num.len << "]";
	for (int i = num.len - 1; i >= 0; --i)
		os << num.a[i];
	if (num.len == 0) os << "0";
	return os;
}

istream& operator >> (istream& is, Biguint& num)
{
	string str;
	is >> str;
	memset(num.a, 0, sizeof num.a);
	num.len = str.length();
	for (int i = 0; i < str.length(); i++)
		num.a[i] = str[str.length() - i - 1] - '0';
	return is;
}
Biguint bigu(int t) {
    Biguint b;
    b.len = 1;
    b.a[0] = 1;
    b*=t;
    return b;
}
int main() {
    isp[1]=0;
    for(int i=2;i<=500;i++) {
        int flag=1;
        for(int j=2;j<i;j++)
            if(i%j==0) flag=0;
        isp[i]=flag;
    }
    for(int i=1;i<=500;i++) {
        int t=i;
        for(int j=2;j<=i;j++)
            while(isp[j]&&t%j==0)
                g[i][j]++,t/=j;
    }
    int T;
    cin>>T;
    while(T--) {
        int n,k;
        cin>>n>>k;
        int tk=k;
        int myFac[505]={};
        for(int i=2;i<=k;i++) {
            while(isp[i]&&tk%i==0)
                myFac[i]++,tk/=i;
        }
        int aFac[505]={};
        for(int i=k*2;i<=n;i+=k) {
            for(int j=2;j<=i;j++)
                if(g[i][j]>myFac[j]) aFac[j]=1;
        }
        for(int i=2;i<=n;i++) {
            myFac[i]+=aFac[i];
            //cout<<myFac[i]<<" ";
        }
        //cout<<endl;
        Biguint ans = bigu(1);
        for(int i=2;i<=n;i++) {
            while(myFac[i]) {
                Biguint x = bigu(i);
                ans=ans*x;
                myFac[i]--;
            }
        }
        cout<<ans<<endl;
    }
}