Java算法 排序问题

用到了Enumeration，代码如下：

import java.util.Enumeration;

/**
* N个要素序列生成，个数为N!
*/
public class PermEnum implements Enumeration {

private int n;
private int c[], k;
private Object[] objs;

public PermEnum(Object[] items) {
n = items.length;
c = new int[n + 1];
for (int i = 0; i <= n; i++) {
c[i] = i;
}
objs = items;
k = 1;
}

public boolean hasMoreElements() {
return k < n;
}

public Object nextElement() {
int i = 0;
if ((k & 1) != 0) {
i = c[k];
}
Object tmp = objs[k];
objs[k] = objs[i];
objs[i] = tmp;

k = 1;
while (c[k] == 0) {
c[k] = k++;
}
c[k]--;
return objs;
}

// TEST输出
public static void main(String[] args) {
String[] strs = {"1", "2", "3", "4"}; // 这里可以自己定义
System.out.println("N=" + strs.length);
Enumeration e = new PermEnum(strs);
int count = 0;
while (e.hasMoreElements()) {
String[] a = (String[]) e.nextElement();
System.out.print("[" + a[0]);
for (int i = 1; i < a.length; i++)
System.out.print(", " + a[i]);
System.out.println("]");
count++;
}
System.out.println("count=" + count);
}

}