題目：輸入一個字串，打印出該字串中字元的所有排列。例如輸入字串abc，則輸出由字元a、b、c所能排列出來的所有字串abc、acb、bac、bca、cab和cba。

/**
 * 
 */
package interview;

import java.util.Arrays;

/**
 * @author clydelou
 * 
 */
public class Test {

	/**
	 * @param args
	 */
	public static void p(int[] a, int index) {
		if (a == null || index < 0)
			return;
		if (index == (a.length - 1))
			System.out.println(Arrays.toString(a));
			
		else {
			for (int i = index; i < a.length; i++) {
				int temp = a[i];
				a[i] = a[index];
				a[index] = temp;

				p(a, index + 1);

				temp = a[i];
				a[i] = a[index];
				a[index] = temp;

			}
		}
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int[] a = { 1, 2, 3 };
		p(a, 0);
	}

}