FZU 1752高速べき乗型取り+乗算の加速

Description
Given A,B,C, You should quickly calculate the result of A^B mod C. (1<=A,B,C<2^63).
Input
There are multiply testcases. Each testcase, there is one line contains three integers A, B and C, separated by a single space.
Output
For each testcase, output an integer, denotes the result of A^B mod C.
Sample Input

3 2 4
2 10 1000

Sample Output

1
24

  a,b,c                                   long long     

 
    
#include 
#include 
using namespace std;
typedef unsigned long long LL;
//    ，          。
LL mul(LL a,LL b,LL m)//     a*b%m;
{
    LL res=0,tmp=a%m;
    while(b)
    {
        if(b&1)
            if((res+=tmp)>=m)
               res-=m;
        if((tmp<<=1)>=m)
            tmp-=m;
        b>>=1;
    }
    return res;
}
LL quick_mod(LL a,LL b,LL m)//   a^b%m
{
    LL ans = 1;
    a%=m;
    while(b)
    {
        if(b%2==1)
        {
            ans=mul(ans,a,m);
            b--;
        }
        b/=2;
        a=mul(a,a,m);
    }
    return ans;
}
int main()
{
    LL a,b,m;
    while(cin>>a>>b>>m){
        cout<