[BASIC-16] 分解质因数

1、如提示所言，先筛出所有素数，然后再分解。

2、“筛法求素数”的思想及方法，可以参看我的另外一篇博客：http://blog.csdn.net/u011506951/article/details/26146595

import java.util.Scanner;

public class Main {

	static final int CONSTANT = 10000;

	static final int[] ARRAY = new int[CONSTANT + 1];

	static int[] primes = new int[1229];

	static {
		createPrimes();
	}

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

		while (scanner.hasNext()) {
			int a = scanner.nextInt();
			int b = scanner.nextInt();

			primeFactors(a, b);
		}
	}

	private static void primeFactors(int a, int b) {
		for (; a <= b; a++) {
			int temp = a;
			System.out.print(a + "=");

			int i = 0;
			while (temp != 1) {
				if (temp % primes[i] == 0) {
					temp /= primes[i];
					System.out.print(primes[i]);
					System.out.print(temp == 1 ? "\r\n" : "*");
				} else {
					i++;
				}
			}
		}
	}

	private static void createPrimes() {
		for (int i = 2; i <= CONSTANT; i++) {
			if (ARRAY[i] == 0) {
				for (int j = i * 2; j <= CONSTANT; j += i) {
					ARRAY[j] = 1;
				}
			}
		}

		int k = 0;
		for (int i = 2; i <= CONSTANT; i++) {
			if (ARRAY[i] == 0) {
				primes[k++] = i;
			}
		}
	}
}

[BASIC-16] 分解质因数,布布扣,bubuko.com

[BASIC-16] 分解质因数

原文：http://blog.csdn.net/u011506951/article/details/26150805