power 快速乘幂

 1 // power
 2 #include<cstdio>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<iostream>
 6 #include<algorithm>
 7 #include<queue>
 8 #include<cmath>
 9 using namespace std;
10 typedef long long ll;
11 ll power (int a,int b,int m)
12 {
13     ll ret=1,t=a;
14     while (b)
15     {
16         if(b&1){
17             ret*=t;
18             ret%=m;
19         }
20         b>>=1;
21         t*=t;
22         t%=m;
23     }
24     return ret%m;
25 }
26 int main()
27 {
28     freopen("1.in","r",stdin);
29     freopen("1.out","w",stdout);
30     int n,m,mod;
31     cin>>n>>m>>mod;
32     ll ans=power(n,m,mod);
33     cout<<ans<<endl;
34     return 0;