Kth Smallest Element Using Min Heap in DSA Javascript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a min heap using JavaScript's built-in array and sort method.

DSA Javascript

const minHeap = arr => arr.sort((a, b) => a [1] b);

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

A-

B>

C+

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '-' causes descending order, not min heap.

Using '<' returns a boolean, leading to incorrect sorting.

To create a min heap, we sort the array in ascending order using (a, b) => a - b.

2fill in blank

medium

Complete the code to extract the smallest element from the min heap array.

DSA Javascript

const extractMin = heap => heap.[1]();

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Apush

Bpop

Cslice

Dshift

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop() removes the largest element at the end, not the smallest.

Using push() adds elements, does not remove.

The smallest element is at the start of the array in a min heap, so use shift() to remove it.

3fill in blank

hard

Fix the error in the code to find the kth smallest element using a min heap.

DSA Javascript

function kthSmallest(arr, k) {
  const heap = arr.slice().sort((a, b) => a - b);
  for (let i = 1; i < k; i++) {
    heap.[1]();
  }
  return heap[0];
}

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

Apop

Bpush

Cshift

Dslice

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop() removes the largest element, not the smallest.

Using push() adds elements, does not remove.

We remove the smallest elements k-1 times using shift(), then return the next smallest at index 0.

4fill in blank

hard

Fill both blanks to create a min heap and extract the kth smallest element.

DSA Javascript

function kthSmallest(arr, k) {
  const heap = arr.slice().sort((a, b) => a [1] b);
  for (let i = 1; i < k; i++) {
    heap.[2]();
  }
  return heap[0];
}

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

A-

B>

Cshift

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' sorts descending, which is max heap behavior.

Using pop() removes last element, not smallest.

Sort ascending with - to build min heap, then remove smallest elements with shift().

5fill in blank

hard

Fill all three blanks to build a min heap, remove k-1 smallest elements, and return the kth smallest.

DSA Javascript

function kthSmallest(arr, k) {
  const heap = arr.slice().sort((a, b) => a [1] b);
  for (let i = 1; i < k; i++) {
    heap.[2]();
  }
  return heap[3];
}

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

A-

Bshift

C[0]

D[k]

Attempts:

3 left

💡 Hint

Common Mistakes

Returning heap[k] is wrong because after removing k-1 elements, kth smallest is at index 0.

Using pop() removes largest element, not smallest.

Sort ascending with -, remove smallest with shift(), then return first element [0].