MP13 progress

Semester 2/Assignments/MP5_CalebFontenot/src/main/java/com/calebfontenot/mp5_calebfontenot/Combinations.java

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+/*
+ * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
+ * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
+ */
+package com.calebfontenot.mp5_calebfontenot;
+
+/**
+ *
+ * @author caleb
+ */
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+
+class Combinations
+{
+
+    private static void findCombinations(String[] A, int i, int k,
+            Set<List<String>> subarrays,
+            List<String> out)
+    {
+        if (A.length == 0 || k > A.length)
+        {
+            return;
+        }
+
+        // base case: combination size is `k`
+        if (k == 0)
+        {
+            subarrays.add(new ArrayList<>(out));
+            return;
+        }
+
+        // start from the next index till the last index
+        for (int j = i; j < A.length; j++)
+        {
+            // add current element `A[j]` to the solution and recur for next index
+            // `j+1` with one less element `k-1`
+            out.add(A[j]);
+            findCombinations(A, j + 1, k - 1, subarrays, out);
+            out.remove(out.size() - 1);         // backtrack
+        }
+    }
+
+    private static Set<List<String>> findCombinations(String[] A, int k)
+    {
+        Set<List<String>> subarrays = new HashSet<>();
+        findCombinations(A, 0, k, subarrays, new ArrayList<>());
+        return subarrays;
+    }
+
+    private static Set<List<String>> findAllCombinations(String[] A)
+    {
+        Set<List<String>> subarrays = new HashSet<>();
+        for (int k = 1; k <= A.length; ++k)
+        {
+            findCombinations(A, 0, k, subarrays, new ArrayList<>());
+        }
+        return subarrays;
+    }
+/** Finds all distinct combinations of all sizes for elements of array.
+ * 
+ * @param A the elements to find their combinations
+ * @return all distinct combinations of the elements, sorted by length. ascending order.
+ */
+    public static ArrayList<String> allCombinations(String[] A)
+    {
+        Set<List<String>> set = findAllCombinations(A);
+        ArrayList<String> all = new ArrayList<String>();
+        Iterator it = set.iterator();
+        while (it.hasNext())
+        {
+            List<String> list = (List<String>) it.next();
+            String s1 = "";
+            for (String s2 : list)
+            {
+                s1 += s2;
+            }
+            all.add(s1);
+        }
+                Collections.sort(all, new Comparator<String>(){
+            @Override
+            public int compare(String o1, String o2)
+            {
+                return o1.length() - o2.length();
+            }
+        });
+        return all;
+    }
+/** Finds all distinct combinations of all sizes for chars of the String.
+ * 
+ * @param A the characters to find their combinations.
+ * @return all distinct combinations of the characters sorted by length, ascending order.
+ */
+    public static ArrayList<String> allCombinations(String a)
+    {
+        String[] A = new String[a.length()];
+        for (int i = 0; i < A.length; ++i)
+        {
+            A[i] = Character.toString(a.charAt(i));
+        }
+        Set<List<String>> set = findAllCombinations(A);
+        ArrayList<String> all = new ArrayList<String>();
+        Iterator it = set.iterator();
+        while (it.hasNext())
+        {
+            List<String> list = (List<String>) it.next();
+            String s1 = "";
+            for (String s2 : list)
+            {
+                s1 += s2;
+            }
+            all.add(s1);
+        }
+        
+        Collections.sort(all, new Comparator<String>(){
+            @Override
+            public int compare(String o1, String o2)
+            {
+                return o1.length() - o2.length();
+            }
+        });
+        return all;
+    }
+
+    public static void main(String[] args)
+    {
+        String[] A =
+        {
+            "1", "2", "3", "4"
+        };
+        int k = 2;
+
+        // process elements from left to right
+        System.out.println(allCombinations(A));
+        System.out.println(allCombinations("1234"));
+
+    }
+}
+

Semester 2/Assignments/MP5_CalebFontenot/src/main/java/com/calebfontenot/mp5_calebfontenot/ShuffleArrayList.java

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+/*
+ * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
+ * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
+ */
+package com.calebfontenot.mp5_calebfontenot;
+
+import java.util.*;
+
+/**
+ *
+ * @author caleb
+ */
+public class ShuffleArrayList {
+
+    public static void shuffle(ArrayList<Number> list)
+    {
+        ArrayList<Integer> selectedIndicies = new ArrayList<Integer>();
+        for (int i = 0; i < list.size(); ++i) {
+            Random rng = new Random();
+            Number random1;
+            do {
+                random1 = rng.nextInt(list.size());
+            } while (selectedIndicies.contains(random1));
+            selectedIndicies.add((int) random1);
+            System.out.println(random1 + ", " + i);
+            Number temp = list.get((int) random1);
+            list.set(i, temp);
+        }
+    }
+
+    public static String checkForDuplicates(ArrayList<Number> list)
+    {
+        // Ensure Array does not include repeat numbers.
+        boolean repeatNumber = false;
+        for (int i = 0; i < list.size(); ++i) {
+            for (int j = 0; j < list.size(); ++j) {
+                if (i != j) {
+                    //System.out.println("Checking " + list.get(i) + " and " + list.get(j));
+                    if (list.get(i) == list.get(j)) {
+                        repeatNumber = true;
+                    }
+                }
+            }
+        }
+        if (repeatNumber) {
+            return "Numbers repeat in ArrayList.";
+        } else {
+            return "Numbers do not repeat in ArrayList.";
+        }
+    }
+
+    public static void main(String[] args)
+    {
+        final int ARRAY_SIZE = 50;
+        ArrayList<Number> list = new ArrayList<>();
+        for (int i = 0; i < ARRAY_SIZE; ++i) {
+            list.add(i + 1); // Fill ArrayList with sequential numbers.
+        }
+
+        System.out.println(list);
+        System.out.println(checkForDuplicates(list));
+        shuffle(list);
+        System.out.println(list);
+        System.out.println(checkForDuplicates(list));
+    }
+
+}