hdu 1097 A hard puzzle（快速幂入门）

A hard puzzle

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 28651    Accepted Submission(s): 10232

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

7 668 800

 

Sample Output

96

 

#include <iostream>#include<stdio.h>using namespace std;long long quick_mod(long long &a,long long &b,long long m){    long long ans=1;    while (b)    {        if (b&1)        {            ans=ans*a%m;            b--;        }        b/=2;        a=a*a%m;    }    return ans;}int main(){    long long a,b;    long long ans;    while (scanf("%lld%lld",&a,&b)!=EOF)    {        ans=quick_mod(a, b, 10);        cout<<ans<<endl;    }    return 0;}