Shortest Path in Unweighted Graph Using BFS in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the queue with the start node.

DSA Typescript

const queue: number[] = [[1]];

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

Astart

B0

Cgraph

Dvisited

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 instead of the start node variable.

Using the whole graph or visited array instead of a single node.

We start BFS by adding the start node to the queue.

2fill in blank

medium

Complete the code to mark the start node as visited.

DSA Typescript

visited[[1]] = true;

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

Aqueue

B0

Cstart

Dnode

Attempts:

3 left

💡 Hint

Common Mistakes

Marking index 0 instead of the start node.

Marking the whole queue or node variable incorrectly.

We mark the start node as visited to avoid revisiting it.

3fill in blank

hard

Fix the error in the loop condition to process nodes until the queue is empty.

DSA Typescript

while (queue.[1] > 0) {

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

Acount

Bsize

Clength()

Dlength

Attempts:

3 left

💡 Hint

Common Mistakes

Using size or count which are not valid for arrays.

Using length() as a function instead of a property.

The length property gives the number of elements in the queue array.

4fill in blank

hard

Fill both blanks to correctly update the distance for neighbors and add them to the queue.

DSA Typescript

distance[neighbor] = distance[current] [1] 1;
queue.[2](neighbor);

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

A+

B-

Cpush

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' instead of '+' for distance update.

Using pop instead of push to add neighbors.

We add 1 to the current node's distance for the neighbor and push the neighbor to the queue.

5fill in blank

hard

Fill all three blanks to correctly check neighbors and update visited and distance arrays.

DSA Typescript

if (!visited[[1]]) {
  visited[[2]] = true;
  distance[[3]] = distance[current] + 1;
}

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

Aneighbor

Bcurrent

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using current or start instead of neighbor in visited or distance updates.

Marking visited or updating distance for the wrong node.

We check if neighbor is not visited, mark neighbor visited, and update neighbor's distance.