implement binary tree and make it balanced

Question

how to do insert random integer between 1 and 10000 to the tree?? I just using scanner.in in code below

 private BinaryTree insert(BinaryTree node, int value)
 {
     if (node == null)
         node = new BinaryTree(value);
     else
     {
         if (value <= node.getValue())
             node.left_child = insert(node.left_child, value);
         else
             node.right_child = insert(node.right_child, value);
     }
     return node;
 }

public static void main(String[] args)

    do    
    {
        //tree operations
        System.out.println("\nTree Operations\n");
        System.out.println("1. insert ");


        int choice = scan.nextInt();            
        switch (choice)
        {
        case 1 : 
            System.out.println("get integer element to insert");
            bst.insert( scan.nextInt() );                     
            break;                                    
        default : 
            System.out.println("Wrong Entry \n ");
            break;   
        }

What exactly is the problem? Are you getting an error? The wrong result? — Mureinik, May 25 '16 at 18:25
I think you need to rethink how are you implementing your BT — J. Pichardo, May 25 '16 at 18:41

score 0 · Answer 1 · answered May 25 '16 at 18:50

I am assuming that your BinaryTree class is as follows:

public BinaryTree{

private int value = null;
private BinaryTree left_child=null;
private BinaryTree right_child=null;
//Also insert getters and setters here

BinaryTree(value){
this.value = value;
}

 private BinaryTree insert(BinaryTree node, int value)
 {
     if (node == null)
         node = new BinaryTree(value);
     else
     {
         if (value <= node.getValue())
             node.left_child = insert(node.left_child, value);
         else
             node.right_child = insert(node.right_child, value);
     }
     return node;
 }
}

In your main method, you should have:

BinaryTree node = new BinaryTree("RootValue");
do{
    //tree operations
    System.out.println("\nTree Operations\n");
    System.out.println("1. insert ");


    int choice = scan.nextInt();            
    switch (choice)
    {
    case 1 : 
        System.out.println("get integer element to insert");
        node = bst.insert( node,scan.nextInt() );                     
        break;                                    
    default : 
        System.out.println("Wrong Entry \n ");
        break;   
    }

I haven't tested this, but I think the primary issue with your code is that your insert method takes two parameters, but you're only passing one in your code. Lemme know if this works.

score -2 · Answer 2 · edited May 25 '16 at 18:48

This is just for insert, you need another process to make it balanced. I would suggest, Take all the integers in an array,Sort the array, and then construct a binary tree in one pass,

private BinaryTree constructBalanced(int a[], int low, int high) {

  if (low > high) return null;
  else {

    int mid = (low + high) / 2;
    BinaryTree root = new BinaryTree(a[mid]);
    root.left = constructBalanced(int a[], low, mid - 1);
    root.right = constructBalanced(int a[], int mid + 1, high);
    return root;
  }
}

implement binary tree and make it balanced

2 Answers2