stubs for ch13

ChrisMayfield · ChrisMayfield · commit 5bc037ba8786 · 2016-04-20T16:55:30.000-04:00
diff --git a/ch13/Deck.java b/ch13/Deck.java
@@ -6,10 +6,6 @@
  */
 public class Deck {
 
-    // This is a class variable so we don't have to create
-    // a new Random object every time we call randomInt.
-    private static Random random = new Random();
-
     private Card[] cards;
 
     /**
@@ -41,65 +37,24 @@ public Card[] getCards() {
     }
 
     /**
-     * Returns a string representation of the deck.
-     */
-    public String toString() {
-        return Arrays.toString(this.cards);
-    }
-
-    /**
-     * Swaps the cards at indexes i and j.
+     * Displays each of the cards in the deck.
      */
-    public void swapCards(int i, int j) {
-        Card temp = this.cards[i];
-        this.cards[i] = this.cards[j];
-        this.cards[j] = temp;
-    }
-
-    /**
-     * Chooses a random number between low and high, including both.
-     */
-    public int randomInt(int low, int high) {
-        int range = high - low + 1;
-        return low + random.nextInt(range);
+    public void print() {
+        for (int i = 0; i < this.cards.length; i++) {
+            System.out.println(this.cards[i]);
+        }
     }
 
     /**
      * Randomly permutes the array of cards.
      */
     public void shuffle() {
-        for (int i = 0; i < this.cards.length - 1; i++) {
-            int j = this.randomInt(i, this.cards.length - 1);
-            this.swapCards(i, j);
-        }
-    }
-
-    /**
-     * Finds the index of the lowest card
-     * between low and high inclusive.
-     */
-    public int indexLowest(int low, int high) {
-        int index = low;
-        Card minCard = this.cards[low];
-        for (int i = low + 1; i <= high; i++) {
-            Card card = this.cards[i];
-            if (card.compareTo(minCard) < 0) {
-                index = i;
-                minCard = card;
-            }
-        }
-        return index;
     }
 
     /**
      * Sorts the cards (in place) using selection sort.
      */
     public void selectionSort() {
-        int high = this.cards.length - 1;
-        for (int i = 0; i < this.cards.length; i++) {
-            int j = this.indexLowest(i, high);
-            this.swapCards(i, j);
-        }
     }
 
     /**
@@ -113,85 +68,16 @@ public Deck subdeck(int low, int high) {
         return sub;
     }
 
-    /**
-     * Combines two previously sorted subdecks.
-     */
-    public static Deck merge(Deck d1, Deck d2) {
-        Card[] c1 = d1.cards;
-        Card[] c2 = d2.cards;
-        Deck result = new Deck(c1.length + c2.length);
-        Card[] c3 = result.cards;
-        int i = 0; // index in c1
-        int j = 0; // index in c2
-
-        // for each index in the result
-        for (int k = 0; k < c3.length; k++) {
-            int choice;
-
-            // determine which card to merge next
-            if (i >= c1.length) {
-                choice = 2;  // c1 is empty
-            } else if (j >= c2.length) {
-                choice = 1;  // c2 is empty
-            } else if (c1[i].compareTo(c2[j]) < 0) {
-                choice = 1;  // c1 is lower
-            } else {
-                choice = 2;  // c2 is lower
-            }
-
-            // store the chosen card in the result
-            if (choice == 1) {
-                c3[k] = c1[i];
-                i++;
-            } else {
-                c3[k] = c2[j];
-                j++;
-            }
-        }
-        return result;
-    }
-
     /**
      * Returns a sorted copy of the deck using merge sort.
      */
     public Deck mergeSort() {
-
-        // 0 or 1 cards, already sorted
-        int len = this.cards.length;
-        if (len < 2) {
-            return this;
-        }
-
-        // cut the deck about in half
-        int mid = len / 2;
-        Deck d1 = this.subdeck(0, mid - 1);
-        Deck d2 = this.subdeck(mid, len - 1);
-
-        // sort each half and merge
-        d1 = d1.mergeSort();
-        d2 = d2.mergeSort();
-        return merge(d1, d2);
+        return this;
     }
 
     /**
      * Reorders the cards (in place) using insertion sort.
      */
     public void insertionSort() {
-        for (int i = 1; i < this.cards.length; i++) {
-            Card card = this.cards[i];
-            this.insert(card, i);
-        }
-    }
-
-    /**
-     * Helper method for insertion sort.
-     */
-    private void insert(Card card, int i) {
-        int j = i;
-        while (j > 0 && card.compareTo(this.cards[j - 1]) < 0) {
-            this.cards[j] = this.cards[j - 1];
-            j--;
-        }
-        this.cards[j] = card;
     }
 }
