hdu 1097 A hard puzzle（快速幂取模）

A hard puzzle

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 29589    Accepted Submission(s): 10655

Problem Description

lcy gives a hard puzzle to feng5166,lwg,JGShining and Ignatius: gave a and b,how to know the a^b.everybody objects to this BT problem,so lcy makes the problem easier than begin.
this puzzle describes that: gave a and b,how to know the a^b's the last digit number.But everybody is too lazy to slove this problem,so they remit to you who is wise.

 

Input

There are mutiple test cases. Each test cases consists of two numbers a and b(0<a,b<=2^30)

 

Output

For each test case, you should output the a^b's last digit number.

 

Sample Input

   
   
   
   

    
    
    
    7 66
8 800
   
   
   
   

 

Sample Output

   
   
   
   

    
    
    
    9
6
   
   
   
   

 

#include<iostream>
#include<cstdio>
using namespace std;

__int64 q_mod(__int64 a,__int64 b)
{
    __int64 s=1;
    while(b>0)
    {
        if(b&1)
            s=a*s%10;
        a=a*a%10;
        b=b/2;
    }
    return s;
}

int main()
{
    __int64 a,b;
    __int64 s;
    while(scanf("%I64d%I64d",&a,&b)==2)
    {
        s=q_mod(a,b);
        printf("%I64d\n",s);
    }
    return 0;
}