JavaScriptAlgorithm/Graphs/ConnectedComponents.js at master · me-hasan/JavaScriptAlgorithm · GitHub

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class GraphUnweightedUndirectedAdjacencyList {

// Unweighted Undirected Graph class

constructor () {

this.connections = {}

}

addNode (node) {

// Function to add a node to the graph (connection represented by set)

this.connections[node] = new Set()

}

addEdge (node1, node2) {

// Function to add an edge (adds the node too if they are not present in the graph)

if (!(node1 in this.connections)) { this.addNode(node1) }

if (!(node2 in this.connections)) { this.addNode(node2) }

this.connections[node1].add(node2)

this.connections[node2].add(node1)

}

DFSComponent (components, node, visited) {

// Helper function to populate the visited set with the nodes in each component

// adding the first visited node in the component to the array

components.push(node)

const stack = [node]

// populating the visited set using DFS (Iterative)

while (stack.length > 0) {

const curr = stack.pop()

visited.add(curr.toString())

for (const neighbour of this.connections[curr].keys()) {

if (!visited.has(neighbour.toString())) { stack.push(neighbour) }

}

connectedComponents () {

// Function to generate the Connected Components

// Result is an array containing 1 node from each component

const visited = new Set()

const components = []

for (const node of Object.keys(this.connections)) {

if (!visited.has(node.toString())) { this.DFSComponent(components, node, visited) }

}

return components

}

export { GraphUnweightedUndirectedAdjacencyList }

// Example

// const graph = new GraphUnweightedUndirectedAdjacencyList()

// graph.addEdge(1, 2) // Component 1

// graph.addEdge(3, 4) // Component 2

// graph.addEdge(3, 5) // Component 2

// const components = graph.connectedComponents()

JavaScriptAlgorithm/Graphs/ConnectedComponents.js at master · me-hasan/JavaScriptAlgorithm · GitHub

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