BST Search Operation in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the current node is null in the BST search function.

DSA Typescript

if (node [1] null) {
  return false;
}

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

A<

B==

C>

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '==' causes wrong logic.

Using '>' or '<' to compare with null is incorrect.

We check if the node is equal to null to know if we've reached a leaf without finding the value.

2fill in blank

medium

Complete the code to return true if the current node's value matches the search value.

DSA Typescript

if (node.value [1] value) {
  return true;
}

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

A<

B!=

C>

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '==' causes wrong results.

Using '>' or '<' here is incorrect.

We return true when the node's value equals the value we are searching for.

3fill in blank

hard

Fix the error in the recursive call to search the left subtree when value is less than node's value.

DSA Typescript

if (value [1] node.value) {
  return searchBST(node.left, value);
}

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

A<

B==

C>

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' causes searching the wrong subtree.

Using '==' or '!=' here is incorrect.

If the value is less than the current node's value, we search the left subtree.

4fill in blank

hard

Fill both blanks to search the right subtree when value is greater than node's value, else return false.

DSA Typescript

if (value [1] node.value) {
  return searchBST(node.right, value);
} else {
  return [2];
}

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

A>

Btrue

Cfalse

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' causes wrong subtree search.

Returning true in else block is incorrect.

If value is greater, search right subtree; otherwise, return false as value not found.

5fill in blank

hard

Fill all three blanks to complete the BST search function with proper conditions and returns.

DSA Typescript

function searchBST(node: TreeNode | null, value: number): boolean {
  if (node [1] null) {
    return false;
  }
  if (node.value [2] value) {
    return true;
  }
  if (value [3] node.value) {
    return searchBST(node.left, value);
  } else {
    return searchBST(node.right, value);
  }
}

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

A==

B!=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '==' for null check causes wrong logic.

Using '!=' to compare node.value and value is incorrect.

Using '>' instead of '<' for subtree decision is wrong.

Check if node == null to return false if null, then if node.value == value return true, then if value < node.value search left else right subtree.