Dijkstra's Algorithm Single Source Shortest Path in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the distance array with infinity values.

DSA Typescript

const distances: number[] = new Array(graph.length).fill([1]);

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

A0

BInfinity

C-1

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Initializing distances with 0 causes incorrect shortest path calculations.

Using null or -1 can cause runtime errors when comparing distances.

We initialize distances with Infinity to represent that nodes are initially unreachable.

2fill in blank

medium

Complete the code to update the distance for a neighbor node if a shorter path is found.

DSA Typescript

if (distances[current] + weight < distances[[1]]) {
  distances[[1]] = distances[current] + weight;
}

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

Aneighbor

Bcurrent

Cweight

Dgraph

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'current' instead of 'neighbor' causes wrong distance updates.

Using 'weight' or 'graph' as index causes runtime errors.

We compare and update the distance of the neighbor node, not the current node.

3fill in blank

hard

Fix the error in the priority queue update to add the neighbor with its new distance.

DSA Typescript

priorityQueue.push({ node: [1], distance: distances[neighbor] });

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

Aneighbor

Bcurrent

Cweight

Ddistances

Attempts:

3 left

💡 Hint

Common Mistakes

Pushing 'current' instead of 'neighbor' causes incorrect traversal order.

Using 'weight' or 'distances' as node causes errors.

We must push the neighbor node with its updated distance into the priority queue.

4fill in blank

hard

Fill both blanks to correctly iterate over neighbors and extract their node and weight.

DSA Typescript

for (const [[1], [2]] of graph[current]) {
  // process neighbor and weight
}

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

Aneighbor

Bweight

Cnode

Ddistance

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping neighbor and weight causes logic errors.

Using incorrect variable names leads to confusion.

Each element in graph[current] is a pair [neighbor, weight], so we destructure accordingly.

5fill in blank

hard

Fill all three blanks to correctly initialize the distances, set the source distance, and start the priority queue.

DSA Typescript

const distances = new Array(graph.length).fill([1]);
distances[[2]] = 0;
priorityQueue.push({ node: [3], distance: 0 });

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

AInfinity

Bsource

C0

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Setting all distances to 0 causes incorrect shortest path results.

Pushing wrong node into the priority queue delays processing.

Distances start at Infinity, source node distance is 0, and we push the source node into the queue.