issue #3474 - adding ternary search data structure

data_structures/ternary tree/java/TernarySearchTreeTest.java

@@ -0,0 +1,182 @@
+import java.util.Scanner;
+import java.util.ArrayList;
+/** class TSTNode **/
+class TSTNode
+{
+    char data;
+    boolean isEnd;
+    TSTNode left, middle, right;
+    /** Constructor **/
+    public TSTNode(char data)
+    {
+        this.data = data;
+        this.isEnd = false;
+        this.left = null;
+        this.middle = null;
+        this.right = null;
+    }
+}
+/** class TernarySearchTree **/
+class TernarySearchTree
+{
+    private TSTNode root;
+    private ArrayList<String> al;
+
+    /** Constructor **/
+    public TernarySearchTree()
+    {
+        root = null;
+    }
+    /** function to check if empty **/
+    public boolean isEmpty()
+    {
+        return root == null;
+    }
+    /** function to clear **/
+    public void makeEmpty()
+    {
+        root = null;
+    }
+    /** function to insert for a word **/
+    public void insert(String word)
+    {
+        root = insert(root, word.toCharArray(), 0);
+    }
+    /** function to insert for a word **/
+    public TSTNode insert(TSTNode r, char[] word, int ptr)
+    {
+        if (r == null)
+            r = new TSTNode(word[ptr]);
+        if (word[ptr] < r.data)
+            r.left = insert(r.left, word, ptr);
+        else if (word[ptr] > r.data)
+            r.right = insert(r.right, word, ptr);
+        else
+        {
+            if (ptr + 1 < word.length)
+                r.middle = insert(r.middle, word, ptr + 1);
+            else
+                r.isEnd = true;
+        }
+        return r;
+    }
+    /** function to delete a word **/
+    public void delete(String word)
+    {
+        delete(root, word.toCharArray(), 0);
+    }
+    /** function to delete a word **/
+    private void delete(TSTNode r, char[] word, int ptr)
+    {
+        if (r == null)
+            return;
+        if (word[ptr] < r.data)
+            delete(r.left, word, ptr);
+        else if (word[ptr] > r.data)
+            delete(r.right, word, ptr);
+        else
+        {
+            /** to delete a word just make isEnd false **/
+            if (r.isEnd && ptr == word.length - 1)
+                r.isEnd = false;
+            else if (ptr + 1 < word.length)
+                delete(r.middle, word, ptr + 1);
+        }
+    }
+    /** function to search for a word **/
+    public boolean search(String word)
+    {
+        return search(root, word.toCharArray(), 0);
+    }
+    /** function to search for a word **/
+    private boolean search(TSTNode r, char[] word, int ptr)
+    {
+        if (r == null)
+            return false;
+        if (word[ptr] < r.data)
+            return search(r.left, word, ptr);
+        else if (word[ptr] > r.data)
+            return search(r.right, word, ptr);
+        else
+        {
+            if (r.isEnd && ptr == word.length - 1)
+                return true;
+            else if (ptr == word.length - 1)
+                return false;
+            else
+                return search(r.middle, word, ptr + 1);
+        }
+    }
+    /** function to print tree **/
+    public String toString()
+    {
+        al = new ArrayList<String>();
+        traverse(root, "");
+        return "\nTernary Search Tree : "+ al;
+    }
+    /** function to traverse tree **/
+    private void traverse(TSTNode r, String str)
+    {
+        if (r != null)
+        {
+            traverse(r.left, str);
+            str = str + r.data;
+            if (r.isEnd)
+                al.add(str);
+            traverse(r.middle, str);
+            str = str.substring(0, str.length() - 1);
+            traverse(r.right, str);
+        }
+    }
+}
+/** class TernarySearchTree **/
+public class TernarySearchTreeTest
+{
+    public static void main(String[] args)
+    {
+        Scanner scan = new Scanner(System.in);
+        /* Creating object of TernarySearchTree */
+        TernarySearchTree tst = new TernarySearchTree();
+        System.out.println("Ternary Search Tree Test\n");
+        char ch;
+        /*  Perform tree operations  */
+        do
+        {
+            System.out.println("\nSelect one of the operation for Ternary Search Tree::");
+            System.out.println("1. To insert a new word in the Ternary Search Tree.");
+            System.out.println("2. To search an already existing word in the Ternary Search Tree.");
+            System.out.println("3. To delete a word from the Ternary Search Tree");
+            System.out.println("4. To check if the Ternary Tree is empty.");
+            System.out.println("5. To make the Ternary Search Tree empty.");
+            int choice = scan.nextInt();
+            switch (choice)
+            {
+                case 1 :
+                    System.out.println("Enter word to insert");
+                    tst.insert( scan.next() );
+                    break;
+                case 2 :
+                    System.out.println("Enter word to search");
+                    System.out.println("Search result : "+ tst.search( scan.next() ));
+                    break;
+                case 3 :
+                    System.out.println("Enter word to delete");
+                    tst.delete( scan.next() );
+                    break;
+                case 4 :
+                    System.out.println("Empty Status : "+ tst.isEmpty() );
+                    break;
+                case 5 :
+                    System.out.println("Ternary Search Tree cleared");
+                    tst.makeEmpty();
+                    break;
+                default :
+                    System.out.println("Wrong Entry \n ");
+                    break;
+            }
+            System.out.println(tst);
+            System.out.println("\nDo you want to continue (Type y or n) \n");
+            ch = scan.next().charAt(0);
+        } while (ch == 'Y'|| ch == 'y');
+    }
+}