[bzoj4522][CQOI2016]密钥破解

来源：互联网发布：日本校园霸凌知乎编辑：程序博客网时间：2024/05/02 01:23

题目描述

这里写图片描述

快速分解

做pollard_rho算法后模拟题意。

#include<cstdio>#include<algorithm>#include<cmath>#define fo(i,a,b) for(i=a;i<=b;i++)using namespace std;typedef long long ll;ll e,d,n,nn,r,c,a,xx,yy,t,p,q,mo;void gcd(ll a,ll b){    if (!b){        xx=1;        yy=0;        t=a;    }    else{        gcd(b,a%b);        swap(xx,yy);        yy-=xx*(a/b);    }}ll getny(ll x,ll y){    gcd(x,y);    xx=(xx%y+y)%y;    return xx;}int rand() {    static int rand_seed=1542071823;    rand_seed+=rand_seed<<1|1;    return rand_seed;}ll qsc(ll x,ll y){    if (!y) return 0;    ll t=qsc(x,y/2);    t=(t+t)%mo;    if (y%2) t=(t+x)%mo;    return t;}ll qsm(ll x,ll y){    if (!y) return 1;    ll t=qsm(x,y/2);    t=qsc(t,t);    if (y%2) t=qsc(t,x);    return t;}ll f(ll x){    return (qsc(x,x)+a)%mo;}ll pollard_rho(ll n){    ll r1,r2,p;    while (1){        a=rand()%100;        r1=r2=2;        do{            r1=f(r1);            r2=f(f(r2));            gcd(abs(r2-r1),n);            p=t;            if (p>1) return p;        }while (r1!=r2);    }}int main(){    scanf("%lld%lld%lld",&e,&n,&c);    mo=n;    p=pollard_rho(n);    q=n/p;    r=(p-1)*(q-1);    d=getny(e,r);    nn=qsm(c,d);    printf("%lld %lld\n",d,nn);}

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