UVA 11375 - Matches

Problem E: Matches

We can make digits with matches as shown below:

Given N matches, find the number of different numbers representable using the matches. We shall only make numbers greater than or equal to 0, so no negative signs should be used. For instance, if you have 3 matches, then you can only make the numbers 1 or 7. If you have 4 matches, then you can make the numbers 1, 4, 7 or 11. Note that leading zeros are not allowed (e.g. 001, 042, etc. are illegal). Numbers such as 0, 20, 101 etc. are permitted, though.

Input

Input contains no more than 100 lines. Each line contains one integer N (1 ≤ N ≤ 2000).

Output

For each N, output the number of different (non-negative) numbers representable if you have N matches.

Sample Input

3
4

Sample Output

2
4

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Problemsetter: Mak Yan Kei

终于AC了这题，可以睡觉了。。。

dp[j] 记录 恰好 J 根的方法数，最后方法数还得注意很多细节

用java大数

import java.util.*;
import java.math.*;
public class code1 {
	public static void main(String[] args) {
		int maxn=2000;
		BigInteger []dp=new BigInteger[maxn+10];
		for(int i=1;i<=maxn;i++) dp[i]=new BigInteger("0");
		dp[0]=new BigInteger("1");
		int []num=new int[10];
		num[0]=6;num[1]=2;num[2]=5;num[3]=5;num[4]=4;
		num[5]=5;num[6]=6;num[7]=3;num[8]=7;num[9]=6;
		for(int j=0;j<=maxn;j++){
	        for(int i=0;i<10;i++){
	            if(i==0&&j==0) continue;
	            if(j+num[i]<=maxn){
	                dp[j+num[i]]=dp[j+num[i]].add(dp[j]);
	            }
	        }
	    }
	    for(int i=2;i<=maxn;i++) dp[i]=dp[i].add(dp[i-1]);
	    for(int i=6;i<=maxn;i++) dp[i]=dp[i].add(new BigInteger("1"));
		Scanner scan=new Scanner(System.in);
		while(scan.hasNextInt()){
			int n=scan.nextInt();
			System.out.println(dp[n]);
		}
		scan.close();
	}
}