HDU 1051 - Rightmost Digit

 1 #include <iostream>
 2 #include <cmath>
 3 using namespace std;
 4 int t,m,p,q;
 5 long long n;
 6 int c[15],ans;
 7 int main()
 8 {
 9     scanf("%d",&t);
10     while(t--)
11     {
12         scanf("%lld",&n);
13         m=n%10;
14         int cnt=0,i;
15         c[++cnt]=m;
16         p=(m*m)%10;
17         while(p!=m)
18         {
19             c[++cnt]=p;
20             p=(p*m)%10;
21         }
22         ans=(n-1)%cnt+1;
23         printf("%d\n",c[ans]);
24     }
25 } 
26 /*
27 3 9 7 1 3
28 4 6 4 6
29 */