快速幂取余

 1 #include<iostream>
 2 #include<cmath>
 3 using namespace std;
 4 
 5 long long f(long long a,long long b,long long n)
 6 {
 7     long long t,y;
 8     t=1;
 9     y=a;
10     while (b!=0)
11     {
12         if (b&1==1)
13             t=t*y%n;
14         y=y*y%n;
15         b=b>>1;
16     }
17     return t;
18 }
19 
20 int PowerMod(int a, int b, int c)
21 {
22     int ans = 1;
23     a = a % c;
24     while(b>0)
25     {
26         if(b % 2 == 1)
27             ans = (ans * a) % c;
28         b = b/2;
29         a = (a * a) % c;
30     }
31     return ans;
32 }
33 
34 int main()
35 {
36     long long a,res;
37     cin >> a;
38     cout << f(a,a,10);
39     return 0;
40 }

借鉴：https://www.cnblogs.com/PegasusWang/archive/2013/03/13/2958150.html

 

转载于:https://www.cnblogs.com/tornado549/p/8723455.html