HDU 4927 Series 1（高精度+杨辉三角）

 1 import java.math.BigInteger;
 2 import java.util.*;
 3 
 4 public class Main 
 5 {
 6     public static BigInteger ans,a,b,flag,temp; 
 7     public static BigInteger[] A = new BigInteger[3005];
 8     public static void main(String[] argv)
 9     {
10         
11         Scanner input = new Scanner(System.in);
12         int T,n;
13         T = input.nextInt();
14         for(int t = 0;t < T;++t)
15         {
16             n = input.nextInt();
17             ans = ans.valueOf(0);
18             a = a.valueOf(1);
19             b = a;
20             for(int i = 1;i <= n;++i)
21             {
22                 A[i] = input.nextBigInteger();
23                 A[i] = A[i].multiply(a);
24                 a = a.multiply(a.valueOf(n-i));
25                 a = a.divide(a.valueOf(i));
26             }
27             flag = flag.valueOf(1);
28             for(int i = n;i >= 1;--i)
29             {
30                 A[i] = A[i].multiply(flag);
31                 ans = ans.add(A[i]);
32                 flag = flag.multiply(flag.valueOf(-1));
33             }
34             System.out.println(ans);
35         }
36     }
37 }