loj2045 「CQOI2016」密钥破解

CQOI 板子大赛之 pollard rho

#include <iostream>
#include <cstdio>
using namespace std;
typedef long long ll;
ll e, N, c, jzm, p, q, r, d, n;
ll gcd(ll a, ll b){
	return !b?a:gcd(b,a%b);
}
ll mul(ll a, ll b, ll p){
	ll re=0;
	while(b){
		if(b&1)	re = (re + a) % p;
		a = (a + a) % p;
		b >>= 1;
	}
	return re;
}
ll pollardRho(){
	ll x=2, y=2;
	while(true){
		x = (mul(x,x,N)+jzm) % N;
		y = (mul(y,y,N)+jzm) % N;
		y = (mul(y,y,N)+jzm) % N;
		if(x==y)	return 1;
		ll re=gcd(x>y?x-y:y-x, N);
		if(re>1)	return re;
	}
}
ll exgcd(ll a, ll b, ll &x, ll &y){
	if(!b){
		x = 1;
		y = 0;
		return a;
	}
	ll re=exgcd(b, a%b, x, y);
	ll z=x;
	x = y;
	y = z - (a / b) * y;
	return re;
}
ll ksm(ll a, ll b, ll p){
	ll re=1;
	while(b){
		if(b&1)	re = mul(re, a, p);
		a = mul(a, a, p);
		b >>= 1;
	}
	return re;
}
int main(){
	cin>>e>>N>>c;
	do{
		jzm++;
		p = pollardRho();
	}while(p==1);
	q = N / p;
	r = (p - 1) * (q - 1);
	ll dddddd;
	exgcd(e, r, d, dddddd);
	d = (d % r + r) % r;
	n = ksm(c, d, N);
	cout<<d<<" "<<n<<endl;
	return 0;
}