ACM International Collegiate Programming Contest, Asia Regional (Tokyo), 2005, Problem A

gistfile1.java

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class Asia2005A {

    public static void main(String[] args) throws FileNotFoundException {
        boolean[] isprime = new boolean[10000];
        ArrayList<Integer> prime = new ArrayList<Integer>();
        for (int i = 0; i < isprime.length; i++) {
            isprime[i] = true;
        }
        for (int i = 2; i < isprime.length; i++) {
            if (isprime[i]) {
                prime.add(i);
                for (int j = i * 2; j < isprime.length; j += i) {
                    isprime[j] = false;
                }
            }
        }

        Scanner s = new Scanner(new File(args[0]));
        while (true) {
            int n = s.nextInt();
            if (n == 0) {
                break;
            }

            int count = 0;
            int sum = 0;
            int min = 0, max = 0;
            //processing
            while (max < prime.size()) {
                sum += prime.get(max++);
                if (sum == n) {
                    count++;
                }
                while (sum > n) {
                    sum -= prime.get(min++);
                    if (sum == n) {
                        count++;
                    }
                }
            }
            System.out.println(count);
        }
    }
}