LightOJ 1028 - Trailing Zeroes (I) http://lightoj.com/volume_showproblem.php?problem=1028 统计约数的个数

LightOJ1028.java

import java.io.BufferedReader;
import java.io.IOError;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class P1028 {

        static final int maxn = 1000100;
	int[] prime = new int[maxn];
	boolean[] check = new boolean[maxn];
	int cnt = 0;

	void getPrime() {
		for (int i = 2; i < maxn; i++) {
			if (check[i] == false)
				prime[cnt++] = i;
			for (int j = 0; j < cnt; j++) {
				if ((long) i * prime[j] >= maxn)
					break;
				check[i * prime[j]] = true;
			}
		}
	}

	public void run() {
		Scanner cin = new Scanner(System.in);
		PrintWriter cout = new PrintWriter(new OutputStreamWriter(System.out));

		getPrime();
		int test = cin.nextInt();
		for (int cas = 1; cas <= test; cas++) {
			long n = cin.nextLong();
			int res = 1;
			for (int i = 0; (long) prime[i] * prime[i] <= n; i++) {
				int cnt = 1;
				while (n % prime[i] == 0) {
					n /= prime[i];
					cnt++;
				}
				res *= (long) cnt;
			}
			if (n > 1)
				res *= 2;
			System.out.println("Case " + cas + ": " + (res - 1));
		}

		cout.flush();
	}

	public static void main(String args[]) {
		new P1028().run();
	}

	class Scanner {

		BufferedReader br;
		StringTokenizer st;

		Scanner(InputStream in) {
			br = new BufferedReader(new InputStreamReader(in));
			eat("");
		}

		void eat(String s) {
			st = new StringTokenizer(s);
		}

		String nextLine() {
			try {
				return br.readLine();
			} catch (IOException e) {
				throw new IOError(e);
			}
		}

		boolean hasNext() {
			while (!st.hasMoreTokens()) {
				String s = nextLine();
				if (s == null)
					return false;
				eat(s);
			}
			return true;
		}

		String next() {
			hasNext();
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}
	}

}