hdu 2837 Calculation

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

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<algorithm>
 4 #include<iomanip>
 5 #include<cmath>
 6 #include<string>
 7 #include<vector>
 8 #define ll __int64
 9 using namespace std;
10 ll euler(int n)
11 {
12     ll ans=1;
13     for(int i=2;i*i<=n;i++)
14     {
15         if(n%i==0)
16         {
17             ans*=i-1;
18             n/=i;
19             while(n%i==0)
20             {
21                 ans*=i;
22                 n/=i;
23             }
24         }
25     }
26     if(n>1) ans*=n-1;
27     return ans;
28 }
29 ll pows(ll a,ll b,ll m)
30 {
31     ll ans=1;
32     while(b)
33     {
34         if(b&1) ans=(ans*a)%m;
35         b>>=1;
36         a=(a*a)%m;
37     }
38     return ans%m;
39 }
40 ll cmp(int a,int b,int m)
41 {
42     ll ans=1;
43     for(int i=1;i<=b;i++)
44     {
45         ans*=a;
46         if(ans>=m) return ans;
47     }
48     return ans;
49 }
50 ll fun(int n,int m)
51 {
52     ll phi=euler(m);
53     if(n<10) return n;
54     ll a=fun(n/10,phi);
55     ll b=cmp(n%10,a,m);
56     if(b>=m) 
57     {
58         ll ans=pows(n%10,a+phi,m);
59         if(ans==0)
60             ans+=m;
61         return ans;
62     }
63     return b;
64 }
65 int main()
66 {
67     int t,i,j,m,n;
68     cin>>t;
69     while(t--)
70     {
71         cin>>n>>m;
72         ll ans=fun(n,m)%m;
73         printf("%I64d\n",ans);
74     }
75     return 0;
76 }
View Code

 

posted @ 2013-07-22 20:40  _随心所欲_  阅读(264)  评论(0)  编辑  收藏  举报