快速幂 HDU3003

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 
 5 using namespace std;
 6 
 7 long long multi(long long a,long long  b)
 8 {
 9     long long mod=b+1;
10     long long ret=1;
11     if(b==0)
12         return 1;
13     while(b>0)
14     {
15         if(b&1)
16             ret=ret*a%mod;
17         a=(a*a)%mod;
18         b=b/2;
19     }
20     return ret;
21 }
22 
23 int main()
24 {
25     long long n;
26     while(cin>>n&&n!=0)
27     {
28         long long  ans=(multi(2,n-1)+1)%n;
29         printf("%I64d
",ans);
30     }
31     return 0;
32 }

View Code

注意大小，用long long 替换 int