# What Is Prim’s Algorithm in Data Structure?

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Heather Bennett

What Is Prim’s Algorithm in Data Structure?

Prim’s algorithm is a widely-used algorithm in data structure that is used to find the minimum spanning tree (MST) of a connected weighted graph. The MST of a graph is a subgraph that includes all the vertices of the original graph but with the minimum possible total edge weight. In simple terms, it helps find the most efficient way to connect all the vertices in a graph while minimizing the total cost or distance.

## How Does Prim’s Algorithm Work?

The algorithm starts by selecting an arbitrary vertex as the starting point and gradually builds up the MST by greedily adding edges that have the minimum weight and connect to vertices not yet included in the MST. The process continues until all vertices are included in the MST.

Let’s break down Prim’s algorithm into steps:

1. Select a starting vertex: Choose any vertex from the graph as the starting point for building our MST.
2. Initialize: Create an empty set to represent the MST and initialize it with only the chosen starting vertex.
3. Find minimum-weight edges: Iterate through all edges connected to vertices in our MST set. Select the edge with minimum weight that connects to a vertex not yet included in our MST.
4. Add selected edge: Add this selected edge and its corresponding vertex to our MST set.
5. Repeat steps 3 and 4: Repeat steps 3 and 4 until all vertices are included in our MST set.

## Pseudocode for Prim’s Algorithm

The following pseudocode illustrates how Prim’s algorithm can be implemented:

```function prim(graph):
create an empty set mstSet
create a priority queue pq

select an arbitrary vertex v and add it to mstSet

while (mstSet does not include all vertices):
for each vertex u adjacent to v:
if u is not in mstSet:
add u and its corresponding edge weight to pq

select the minimum-weight edge from pq
let (v, u) be this edge

if u is not in mstSet:
add the edge (v, u) to the MST

set v = u
```

## Applications of Prim’s Algorithm

Prim’s algorithm has various practical applications, including:

• Finding minimum-cost network connections
• Solving problems related to cluster analysis
• Designing efficient network infrastructure