Our Mathematical Selection code in Java.
Mathematical Selection Class File:
package miscellaneous;
import java.util.ArrayList;
import java.util.List;
public class Selection {
public String[] words;
public int r; // min length of word
protected List<String[]> complete_group;
private int i;
public Selection() {
}
public List<String[]> groupSelection(String[] candidates, int size) {
words = candidates;
r = size;
complete_group = new ArrayList<>();
i = 0;
recursiveFillUp(new ArrayList<>());
return complete_group;
}
// pick elements recursively
protected void recursiveFillUp(List<String> temp) {
List<String>[] picked_elements = new List[words.length];
int j = i;
while (j < words.length) {
picked_elements[j] = new ArrayList<>();
picked_elements[j].addAll(temp);
picked_elements[j].add(words[j]);
// recoil factor
if (i >= words.length) {
i = j;
}
// satisfied yet?
if (picked_elements[j].size() == r) {
complete_group.add(picked_elements[j].toArray(new String[0]));
} else if (picked_elements[j].size() < r) {
recursiveFillUp(picked_elements[j]);
}
j++;
}
if (picked_elements[--j] != null && picked_elements[j].size() == r) {
i++; // keep recoil factor straightened out
}
}
}Main Class:
package miscellaneous;
import java.util.Arrays;
import java.util.List;
public class Miscellaneous {
public static void main(String[] args) {
String[] goods = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
Selection pick = new Selection();
List<String[]> result = pick.groupSelection(goods, 3);
System.out.println(Arrays.toString(pick.words) + " selection " + pick.r + ":\n");
int i = 0;
for (String[] set : result) {
System.out.println(++i + ": " + Arrays.toString(set) + ";");
}
System.out.println("\nNumber of ways is " + result.size() + ".");
}
}Try it out!
Elegance (0.0)
