Question

(Java) Write a method with two parameters, prefix ( a string) and levels(a non-negative integer). The method prints the string prefix followed by "section numbers" of the form 1.1,1.2,1.3 and so on. Start by printing:
Box: 1.1
Box: 1.2
all the way to Box:9.9

Answer 1

I think this problem has to do with finding permutations. Lexicographical permutations with repetitions to be exact.

For example perm(A,B,C):
AAA
AAB
AAC
ABA
ABB
ABC
ACA
ACB
ACC
CAA
CAB
CAC
CBA
CBB
CBC
CCA
CCB
CCC

If you solve this could you please post the code?

Answer 2

Regrettably I don't have time to finish this, you need to sort the list and implement a correct print method:
import java.util.List;
import java.util.ArrayList;
public class Permutations {
private String a;
private int n;
public Permutations(String a, int n) {
this.a = a;
this.n = n;
}
public List<String> getVariations() {
int l = a.length();
int permutations = (int)Math.pow(l, n);
char[][] table = new char[permutations][n];
for(int x = 0; x < n; x++) {
int t2 = (int)Math.pow(l, x);
for (int p1 = 0; p1 < permutations;) {
for (int al = 0; al < l; al++) {
for (int p2 = 0; p2 < t2; p2++) {
table[p1][x] = a.charAt(al);
p1++;
}
}
}
}
List<String> result = new ArrayList<String>();
for(char[] permutation : table) {
result.add(new String(permutation));
}
return result;
}
public static void printWithPrefix(String prefix, int length) {
Permutations gen = new Permutations("123456789", length);
List<String> v = gen.getVariations();
for (String s : v) {
System.out.println(prefix + ": " + s);
}
}
public static void main(String[] args) {
printWithPrefix("Box", 3);
}
}