问题链接:https://vjudge.net/problem/HDU-1061
问题简述:求n的n次方的个位数。
Get:可以用快速幂,也可以找规律。
方法一:找规律
相关链接:https://blog.csdn.net/feynman1999/article/details/69388463
https://blog.csdn.net/yanqianglifei/article/details/77738732
(大佬们都讲得很详细,我就不写了)
AC代码:(链接里用的是小循环,这里我用的是大循环(以20为一个周期))
#include <iostream>
using namespace std;
int main()
{
int T,N,a[21] = { 0,1,4,7,6,5,6,3,6,9,0,1,6,3,6,5,6,7,4,9,0 };
cin >> T;
while (T--)
{
cin >> N;
cout << a[N % 20] << endl;
}
}
方法二:快速幂
相关链接:https://blog.csdn.net/whjkm/article/details/42803805
代码:
#include <iostream>
using namespace std;
int k(long long a, long long b, long long c)
{
int cnt = 1;
a = a % c;
while (b)
{
if (b % 2)
{
cnt = cnt * a%c;
}
b = b / 2;
a = a * a%c;
}
return cnt;
}
int main()
{
int n,a;
cin >> n;
while (n--)
{
cin >> a;
int s = k(a, a, 10);
cout << s << endl;
}
}