hdu 2837 Calculation

公式：a^b%p=a^(b%phi(p)+phi(p))%p   b>=phi(p)

 #include<iostream>
 #include<stdio.h>
 #include<algorithm>
 #include<iomanip>
 #include<cmath>
 #include<string>
 #include<vector>
 #define ll __int64
 using namespace std;
 ll euler(int n)
 {
     ll ans=;
     for(int i=;i*i<=n;i++)
     {
         if(n%i==)
         {
             ans*=i-;
             n/=i;
             while(n%i==)
             {
                 ans*=i;
                 n/=i;
             }
         }
     }
     if(n>) ans*=n-;
     return ans;
 }
 ll pows(ll a,ll b,ll m)
 {
     ll ans=;
     while(b)
     {
         if(b&) ans=(ans*a)%m;
         b>>=;
         a=(a*a)%m;
     }
     return ans%m;
 }
 ll cmp(int a,int b,int m)
 {
     ll ans=;
     for(int i=;i<=b;i++)
     {
         ans*=a;
         if(ans>=m) return ans;
     }
     return ans;
 }
 ll fun(int n,int m)
 {
     ll phi=euler(m);
     if(n<) return n;
     ll a=fun(n/,phi);
     ll b=cmp(n%,a,m);
     if(b>=m)
     {
         ll ans=pows(n%,a+phi,m);
         if(ans==)
             ans+=m;
         return ans;
     }
     return b;
 }
 int main()
 {
     int t,i,j,m,n;
     cin>>t;
     while(t--)
     {
         cin>>n>>m;
         ll ans=fun(n,m)%m;
         printf("%I64d\n",ans);
     }
     return ;
 }