// Allison Obourn
// CSE 143 - lecture 20
// An IntSearchTree object represents an entire binary search tree of ints.
// Class invariant: 
//    - nodes to the left of a root have smaller values
//    - nodes to the right of a root have larger values
//    - there are no duplicates

public class IntBinarySearchTree {
   private IntTreeNode overallRoot;
   
   // Constructs an empty binary tree.
   public IntBinarySearchTree() {
      overallRoot = null;
   }
   
   // Constructs a binary tree with the given node as its root.
   // Note: this is hacky and just useful for testing
   public IntBinarySearchTree(IntTreeNode root) {
      overallRoot = root;
   }
   
   // Returns true if the value is in this tree, false otherwise.
   public boolean contains(int value) {
      return contains(overallRoot, value);
   }
   
   // Returns true if the value is in the tree starting at the
   // specified root.
   private boolean contains(IntTreeNode root, int value) {
      if(root == null) {
         return false;
      } else if(root.data == value) {
         return true;
      } else if(root.data > value) {
         return contains(root.left, value);
      } else {
         return contains(root.right, value);
      }
   }
   
   // Adds the given value to this BST.
   // Post: the tree is still a valid BST
   public void add(int value) {
      overallRoot = add(overallRoot, value);
   }
   
   // Adds the given value to the BST starting at the given root.
   // Post: the tree is still a valid BST
   private IntTreeNode add(IntTreeNode root, int value) {
      if(root == null) {
         root = new IntTreeNode(value);
      } else if(root.data > value) {
         root.left = add(root.left, value);
      } else if(root.data > value) {
         root.right = add(root.right, value);
      }
      return root;
   }
   
   // Prints a pre-order traversal of this tree.
   public void printPreorder() {
      printPreorder(overallRoot);
      System.out.println();
   }
   
   // Prints a pre-order traversal of the tree starting at the specified root
   private void printPreorder(IntTreeNode root) {
      if(root != null) {
         System.out.print(root.data + " ");
         printPreorder(root.left);
         printPreorder(root.right);
      }
   }
   
   // Prints an in-order traversal of this tree.
   public void printInorder() {
      printInorder(overallRoot);
      System.out.println();
   }
   
   // Prints an in-order traversal of the tree starting at the specified root
   private void printInorder(IntTreeNode root) {
      if(root != null) {
         printInorder(root.left);
         System.out.print(root.data + " ");
         printInorder(root.right);
      }
   }

   // Prints a post-order traversal of this tree.
   public void printPostorder() {
      printPostorder(overallRoot);
      System.out.println();
   }
   
   // Prints a post-order traversal of the tree starting at the specified root
   private void printPostorder(IntTreeNode root) {
      if(root != null) {
         printPostorder(root.left);
         printPostorder(root.right);
         System.out.print(root.data + " ");
      }
   }
}