模板题

注意Pollard_Rho()的写法

第一次比较应该是 a-0步，b-1步

#include <cstdio>
#include <cstdlib>
#include <algorithm>

using std::max;

typedef long long ll;

int T;
ll N;

ll Pri[10]={2LL, 3LL, 5LL, 7LL, 11LL, 13LL, 17LL, 19LL, 23LL, 29LL};

ll Rand(){
    return rand()*1034567890LL+(ll)(rand());
}

ll Rand(ll l, ll r){
    return Rand()%(r-l+1LL)+l;
}

ll abs(ll a){
    return (a>0LL)?a:(-a);
}

ll gcd(ll a, ll b){
    return (b==0LL)?a:gcd(b, a%b);
}

ll MOD;

ll sr;
ll sum(ll a, ll b){
    sr=a+b;
    if(sr>=MOD) sr-=MOD;
    return sr;
}

ll mul(ll a, ll b){
    ll k=(ll)((1.0L*a*b)/(1.0L*MOD));
    ll r=a*b-k*MOD;
    if(r<0) r+=MOD;
    return r;
}

ll pow(ll a, ll k){
    ll ret=1LL, t=a;
    while(k>0LL){
        if(k&1LL)   ret=mul(ret, t);
        t=mul(t, t);
        k>>=1;
    }
    return ret;
}

bool Miller_Rabin(ll n){
    if(n<2LL)   return false;
    if(n==2LL)  return true;
    if((n&1LL)==0LL)    return false;
    MOD=n;
    int k=0;
    ll m=n-1, a;
    while((m&1LL)==0LL) {++k;m>>=1;}
    bool ret=true;
    for(int i=0, j;i<10 && ret;++i){
        if(Pri[i]>=n)   break;
        a=pow(Pri[i], m);
        if(a==1LL)  continue;
        for(j=0;j<k;++j){
            if(a==n-1LL)    break;
            a=mul(a, a);
        }
        if(j==k)    ret=false;
    }
    return ret;
}

ll Pollard_Rho(ll c, ll n){
    MOD=n;
    ll a=Rand(1LL, n-1LL), b=sum(mul(a, a), c), d;
    while(a!=b){
        d=gcd(abs(a-b), n);
        if(d>1LL)   return d;
        a=sum(mul(a, a), c);
        b=sum(mul(b, b), c);b=sum(mul(b, b), c);
    }
    return n;
}

ll Rho(ll n){
    if(Miller_Rabin(n)) return n;
    ll t=n;
    while(t==n) t=Pollard_Rho(Rand(1LL, n-1LL), n);
    return max(Rho(t), Rho(n/t));
}

int main(){
    
    srand(1075757);
    
    scanf("%d", &T);
    
    while(T--){
        
        scanf("%lld", &N);
        
        if(Miller_Rabin(N)) puts("Prime");
        else    printf("%lld\n", Rho(N));
        
    }   
    
    return 0;
}