Hdu 5568 sequence2 高精度 dp

sequence2

Time Limit: 20 Sec

Memory Limit: 256 MB

题目连接

http://acm.hdu.edu.cn/showproblem.php?pid=5568

Description

Given an integer array bi with a length of n, please tell me how many exactly different increasing subsequences.

P.S. A subsequence bai(1≤i≤k) is an increasing subsequence of sequence bi(1≤i≤n) if and only if 1≤a1<a2<...<ak≤n and ba1<ba2<...<bak.
Two sequences ai and bi is exactly different if and only if there exist at least one i and ai≠bi.

Input

Several test cases(about 5)

For each cases, first come 2 integers, n,k(1≤n≤100,1≤k≤n)

Then follows n integers ai(0≤ai≤109)

Output

For each cases, please output an integer in a line as the answer.

Sample Input

3 2
1 2 2
3 2
1 2 3

Sample Output

2
3

HINT

 

题意

给你n个数，问你有多少个长度为k的上升子序列，需要高精度

题解：

数据范围只有100，所以直接暴力就好了

但是要高精度，所以我们就直接使用java就好了

代码：

import java.util.*;
import java.math.*;

public class Main
{
    static int n,k;
    static int[] a = new int[102];
    static BigInteger[][] dp = new BigInteger[105][105];
    static BigInteger ans;
    public static void main(String[] args)
    {
        Scanner IN=new Scanner(System.in);
        while(IN.hasNext())
        {
            n = IN.nextInt();
            k = IN.nextInt();
            for(int i=1;i<=n;i++)
                a[i] = IN.nextInt();
            for(int i=0;i<=n+3;i++)
                for(int j=0;j<=n+3;j++)
                    dp[i][j]=BigInteger.ZERO;
            ans = BigInteger.ZERO;
            for(int i=1;i<=n;i++)
            {
                dp[i][1]=BigInteger.ONE;
                for(int j=1;j<i;j++)
                {
                    if(a[j]<a[i])
                    {
                        for(int t=1;t<=j+1;t++)
                        {
                            dp[i][t+1]=dp[i][t+1].add(dp[j][t]);
                        }
                    }
                }
            }
            for(int i=1;i<=n;i++)
                ans = ans.add(dp[i][k]);
            System.out.println(ans);
        }
    }
}