2019-05-02 12:53:40 +03:00
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class Graph {
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2020-05-03 09:05:12 +02:00
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constructor () {
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this.adjacencyMap = {}
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}
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addVertex (v) {
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this.adjacencyMap[v] = []
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}
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containsVertex (vertex) {
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return typeof (this.adjacencyMap[vertex]) !== 'undefined'
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}
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addEdge (v, w) {
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let result = false
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if (this.containsVertex(v) && this.containsVertex(w)) {
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this.adjacencyMap[v].push(w)
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this.adjacencyMap[w].push(v)
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result = true
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2019-05-02 12:53:40 +03:00
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}
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2020-05-03 09:05:12 +02:00
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return result
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}
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printGraph () {
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const keys = Object.keys(this.adjacencyMap)
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for (const i of keys) {
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const values = this.adjacencyMap[i]
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let vertex = ''
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for (const j of values) { vertex += j + ' ' }
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console.log(i + ' -> ' + vertex)
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2019-05-02 12:53:40 +03:00
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}
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2020-05-03 09:05:12 +02:00
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}
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2020-05-18 10:15:53 +05:30
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/**
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* Prints the Breadth first traversal of the graph from source.
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*
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* @param {number} source The source vertex to start BFS.
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*/
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bfs (source) {
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const queue = []
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const visited = new Set()
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queue.unshift([source, 0]) // level of source is 0
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visited.add(source)
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while (queue.length) {
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const front = queue[0]
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const node = front[0]
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const level = front[1]
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queue.shift() // remove the front of the queue
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console.log(`Visited node ${node} at level ${level}.`)
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for (const next of this.adjacencyMap[node]) {
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if (!visited.has(next)) { // not visited
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queue.unshift([next, level + 1]) // level 1 more than current
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visited.add(next)
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}
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}
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}
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}
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2019-05-02 12:53:40 +03:00
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}
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const example = () => {
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2020-05-03 09:05:12 +02:00
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const g = new Graph()
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g.addVertex(1)
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g.addVertex(2)
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g.addVertex(3)
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2020-05-18 10:15:53 +05:30
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g.addVertex(4)
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g.addVertex(5)
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2020-05-03 09:05:12 +02:00
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g.addEdge(1, 2)
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g.addEdge(1, 3)
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2020-05-18 10:15:53 +05:30
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g.addEdge(2, 4)
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g.addEdge(2, 5)
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console.log('Printing the adjacency list:\n')
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2020-05-03 09:05:12 +02:00
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g.printGraph()
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2020-05-18 10:15:53 +05:30
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// perform a breadth first search
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console.log('\nBreadth first search at node 1:\n')
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g.bfs(1)
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2020-05-03 09:05:12 +02:00
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}
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2020-05-04 10:48:45 +05:30
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example()
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