Codeforces 23E Tree（树型DP）

 1 import java.util.*;
 2 import java.io.*;
 3 import java.math.*;
 4 
 5 public class Main{
 6     static final int maxn = 710;
 7     static BigInteger dp[][] = new BigInteger[maxn][maxn];
 8     static int v[][] = new int[maxn][maxn];
 9     static int sum[] = new int[maxn];
10     static int n;
11     
12     static void dfs(int x, int pre){ int y;
13         sum[x] = 1;
14         for(int i = 0; i <= n; ++i) dp[x][i] = BigInteger.ONE;
15         for(int i = 1; i <= v[x][0]; ++i){
16             y = v[x][i];
17             if(y == pre) continue;
18             dfs(y, x);
19             for(int j = sum[x]; j >= 0; --j)
20                 for(int k = sum[y]; k >= 0; --k){
21                     dp[x][j + k] = dp[x][j + k].max(dp[x][j].multiply(dp[y][k]));
22             }
23             sum[x] += sum[y];
24         }
25         for(int i = 1; i <= sum[x]; ++i) dp[x][0] = dp[x][0].max(dp[x][i].multiply(BigInteger.valueOf(i)));
26     }
27     
28     public static void main(String[] args){
29         Scanner in = new Scanner(System.in);
30         n = in.nextInt();
31         for(int i = 1; i <= n; ++i){
32             v[i][0] = 0;
33         }
34         for(int i = 1; i < n; ++i){
35             int x = in.nextInt();
36             int y = in.nextInt();
37             v[x][++v[x][0]] = y;
38             v[y][++v[y][0]] = x;
39         }
40         dfs(1, 0);
41         System.out.println(dp[1][0]);
42     }
43 
44 }