@Test
public void test2() {
Set<String> res = new HashSet<String>();
res = Permute.permutation("abc");
String[] out = res.toArray(new String[res.size()]);
String[] exp = {"bca", "acb", "abc", "cba", "bac", "cab"};
assertArrayEquals(exp, out);
}
@Test
public void test1() {
Set<String> res = new HashSet<String>();
res = Permute.permutation("111b");
String[] out = res.toArray(new String[res.size()]);
String[] exp = {"b111", "1b11", "111b", "11b1"};
assertArrayEquals(exp, out);
}