Binary Tree Node Structure in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a class property for the node's value.

DSA Typescript

class TreeNode {
  value: [1];
  constructor(value: number) {
    this.value = value;
  }
}

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Aboolean

Bany

Cnumber

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using string or boolean instead of number for the value type.

The node's value is a number, so the property type should be number.

2fill in blank

medium

Complete the code to declare the left child property of the binary tree node.

DSA Typescript

class TreeNode {
  left: [1];
  constructor() {
    this.left = null;
  }
}

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ATreeNode | null

Bnumber

Cboolean

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using just TreeNode without allowing null.

Using primitive types like number or string.

The left child is either another TreeNode or null if no child exists.

3fill in blank

hard

Fix the error in the constructor to properly initialize the right child property.

DSA Typescript

class TreeNode {
  right: TreeNode | null;
  constructor() {
    this.right = [1];
  }
}

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Aundefined

Bnull

C0

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Initializing with undefined or 0 instead of null.

The right child should be initialized to null to indicate no child.

4fill in blank

hard

Fill both blanks to declare left and right children with correct types and initialize them to null.

DSA Typescript

class TreeNode {
  left: [1];
  right: [2];
  constructor() {
    this.left = null;
    this.right = null;
  }
}

Drag options to blanks, or click blank then click option'

ATreeNode | null

Bnumber

Cstring

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using different types for left and right children.

Not allowing null as a possible value.

Both left and right children are either TreeNode or null.

5fill in blank

hard

Fill all three blanks to complete the TreeNode class with value, left, and right properties properly typed and initialized.

DSA Typescript

class TreeNode {
  value: [1];
  left: [2];
  right: [3];
  constructor(value: number) {
    this.value = value;
    this.left = null;
    this.right = null;
  }
}

Drag options to blanks, or click blank then click option'

Anumber

BTreeNode | null

Cstring

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using string or boolean for value.

Not allowing null for children.

The value is a number, and both left and right children are TreeNode or null.