Permutation of a given string Complexity = O(n!)

gistfile1.java

public static void permString(String p, String t){
    int size = t.length();
    if (size == 0){
        System.out.println(p);
    } else {
        for (int i=0; i<size; i++){
            perm(p + t.charAt(i),
                t.substring(0,i) + t.substring(i+1));
        }
    }
}