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What is the relation between EXTRACT-MIN operation and DECREASE-KEY operations in priority queue? I encountered this in the lecture for minimum spanning problem using Prim’s algorithm.
The professor from MIT refers to it at point 01:07:16 seconds in the video but I am not getting it. Can some one please clear this up for me?
P.S: I feel comfortable with my understanding of Priority Queues otherwise.
This sequence:
Has a simple meaning:
What it basically does is to make sure a certain node gets to the top of the queue and then removes it.
In Prim’s algorithm,
DECREASE-KEYis used to update the weight of nodes not yet included in the tree. As a result, a node that was thought to be too far may now move closer to the top of the queue (and therefore would beEXTRACT-MINed sooner).I can’t view the video right now, but my guess is that what your professor meant is that
DECREASE-KEYincreases the chances of a node to beEXTRACT-MINed and is in fact used for the same reason, and hence a sort of relationship.