OJ-Problems-Source/HDOJ/3307_autoAC.cpp
2016-09-01 20:54:35 +08:00

70 lines
1.3 KiB
C++

#include <cstdio>
#include <cstring>
#include <cmath>
#include <iostream>
#include <algorithm>
using namespace std;
#define LL __int64
const LL maxn=1001;
LL e[maxn],t;
LL gcd(LL a,LL b)
{
return b==0?a:gcd(b,a%b);
}
LL euler_phi(LL n)
{
LL m=(LL)sqrt(n+0.5);
LL i,ans=n;
for(i=2;i<=m;i++)
if(n%i==0)
{
ans=ans/i*(i-1);
while(n%i==0)n/=i;
}
if(n>1)ans=ans/n*(n-1);
return ans;
}
void find(LL n)
{
LL m=(LL)sqrt(n+0.5);
for(LL i=1;i<m;i++)
if(n%i==0){e[t++]=i;e[t++]=n/i;}
if(m*m==n)e[t++]=m;
}
LL pow_mod(LL a,LL b,LL mod)
{
LL s=1;
while(b)
{
if(b&1)
s=(s*a)%mod;
a=(a*a)%mod;
b=b>>1;
}
return s;
}
int main()
{
LL a,x,y;
while(cin>>x>>y>>a)
{
LL m,phi,i;
if(y==0){cout<<"1"<<endl;continue;}
m=a/gcd(y/(x-1),a);
if(gcd(m,x)!=1){cout<<"Impossible!"<<endl;continue;}
phi=euler_phi(m);
t=0;
find(phi);
sort(e,e+t);
for(i=0;i<t;i++)
{
if(pow_mod(x,e[i],m)==1)
{
cout<<e[i]<<endl;
break;
}
}
}
return 0;
}