N！的全排列算法(Java实现)

public class TestSort {
String[] list;
StringBuffer sb;
int len, start;

TestSort(String in) {
len = Integer.parseInt(in);
list = new String[len];
for (int i = 0; i < len; i++) list[i] = String.valueOf(i + 1);
permutation(0,len-1);
}

void swap(int c1, int c2) {
String temp = list[c1];
list[c1] = list[c2];
list[c2] = temp;
}

void permutation(int m,int n) {
if (m==n) {
sb = new StringBuffer();
for (int i = 0; i < len; i++) sb.append(list[i]);
sb.append(" ");
System.out.print(sb);
} else {
for (int i = m; i<=n; i++) {
swap(m, i);//交换
permutation(m+1,n);
swap(m,i);//还原
}
}
}

public static void main(String args[]) {
new TestSort("3");
}
}