Dijkstra's Algo in 2 Minutes | All you need to know #dijkstra #graph #dsa #algorithms #shorts #recap

Added: 2026-05-21

[00:00:00]Hello everyone. Let us have a quick recap about the Dijkstra's algorithm.

[00:00:04]Just the way the Google Map works that given a source as well as a destination, it finds you the smallest path.

[00:00:10]This particular Dijkstra works in the same way.

[00:00:13]So, what is this Dijkstra's algorithm basically? It is a single source shortest path algorithm that helps you to find the shortest path from one particular source node to all the other nodes.

[00:00:24]Which data structure does this Dijkstra works on? This particular Dijkstra basically works on the weighted graph.

[00:00:30]And which programming paradigm does it follow?

[00:00:33]Because it is an optimization problem, because you are trying to find the minimum travel cost or minimum distance, so this is a minimization problem, so we can apply greedy over here. And how does it apply greedy? Because all the time it is trying to pick the local optimal nearest neighbor first. Okay. Now, how does it work?

[00:00:53]This particular Dijkstra's algorithm starts with the source node and assigns the value like the source to source is zero and to all other node, the distance becomes infinite. Now, it goes to the nearest unvisited node and it relaxes all the edges. And what do I mean by relaxing? Relaxing means updating the distance if a shorter distance is found.

[00:01:14]Then once the relaxation is done, it keeps on doing the same thing until and unless all the nodes are covered. This is the way this Dijkstra is working.

[00:01:23]Now, if you see one of the major drawbacks of Dijkstra is it cannot work on negative weighted edge. But when you will be seeing the Bellman-Ford, this particular drawback will be gone because Bellman-Ford can tackle this thing.

[00:01:35]Now, what about the time complexity of this Dijkstra?

[00:01:39]If we are doing using the adjacency list concept, the time complexity is order of E log V, where E is the number of edges and V is the number of vertices. And if we are doing using the adjacency matrix, in that case the time complexity becomes order of V squared.

[00:01:54]So, this is all the things you wanted to know or you needed to know when we talked about this Dijkstra.

[00:02:01]So, I hope all the things are clear and I have a detailed video on this Dijkstra available on the doubt playlist. I'm putting that in the pin comment. You can check out. Thank you for watching and stay tuned for the next video.