Cod sursa(job #2467820)
| Utilizator | Data | 5 octombrie 2019 08:48:26 | |
|---|---|---|---|
| Problema | Invers modular | Scor | 0 |
| Compilator | cpp-64 | Status | done |
| Runda | Arhiva educationala | Marime | 0.67 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin("inversmodular.in");
ofstream fout("inversmodular.in");
int LogP(int a, int n,int mod)
{
int p=1;
while(n)
{
if(n%2==1)
p=1LL*p*a%mod;
n/=2;
a=1LL *a*a%mod;
}
return p;
}
int phi(int n)
{
int p,sol;
sol=n;
p=2;
for(p = 2;n>1 && p*p<=n;p++){
if(n%p==0)
sol=sol/p*(p-1);
while(n%p==0)
n/=p;
}
if(n > 1)
sol = sol / n *(n-1);
return sol;
}
int main()
{
int a,n;
fin >> a >> n;
int phii;
phii=phi(n);
fout<<LogP(a,phii-1,n)<<"\n";
return 0;
}
