Add Graph BFS algorithm (#169)

* Add Graph BFS algorithm

* updating DIRECTORY.md

* Fix failing tests

* updating DIRECTORY.md

* Fix further failing tests

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
This commit is contained in:
Sahil
2020-05-18 10:15:53 +05:30
committed by GitHub
parent 25dac3a1e3
commit cb0aff9ec2

View File

@ -30,6 +30,31 @@ class Graph {
console.log(i + ' -> ' + vertex)
}
}
/**
* Prints the Breadth first traversal of the graph from source.
*
* @param {number} source The source vertex to start BFS.
*/
bfs (source) {
const queue = []
const visited = new Set()
queue.unshift([source, 0]) // level of source is 0
visited.add(source)
while (queue.length) {
const front = queue[0]
const node = front[0]
const level = front[1]
queue.shift() // remove the front of the queue
console.log(`Visited node ${node} at level ${level}.`)
for (const next of this.adjacencyMap[node]) {
if (!visited.has(next)) { // not visited
queue.unshift([next, level + 1]) // level 1 more than current
visited.add(next)
}
}
}
}
}
const example = () => {
@ -37,8 +62,17 @@ const example = () => {
g.addVertex(1)
g.addVertex(2)
g.addVertex(3)
g.addVertex(4)
g.addVertex(5)
g.addEdge(1, 2)
g.addEdge(1, 3)
g.addEdge(2, 4)
g.addEdge(2, 5)
console.log('Printing the adjacency list:\n')
g.printGraph()
// perform a breadth first search
console.log('\nBreadth first search at node 1:\n')
g.bfs(1)
}
example()