UVA 11375 Matches

白书上的例题，实际上就是一个背包问题，不过要注意高精度问题，上java就没问题了。

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

public class Main {
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        int n;
        BigInteger d[] = new BigInteger[2010];
        int c[] = {6, 2, 5, 5, 4, 5, 6, 3, 7, 6};
        for(int i = 0; i <= 2000; i++) {
            d[i] = BigInteger.ZERO;
        }
        d[0] = BigInteger.ONE;
        for(int i = 0; i <= 2000; i++) {
            for(int j = 0; j < 10; j++) {
                if(!(i == 0 && j == 0) && i + c[j] <= 2000) {
                    d[i+c[j]] = d[i+c[j]].add(d[i]);
                }
            }
        }
        BigInteger ans[] = new BigInteger[2010];
        ans[0] = BigInteger.ZERO;
        for(int i = 1; i <= 2000; i++)
            ans[i] = ans[i-1].add(d[i]);
        while(in.hasNext()) {
            n = in.nextInt();
            if(n >= 6)
                System.out.println(ans[n].add(BigInteger.ONE));
            else
                System.out.println(ans[n]);
        }
    }
}