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BreadthFirstSearch.js
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BreadthFirstSearch.js
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import Queue from '../Data-Structures/Queue/Queue'
/**
* Breadth-first search is an algorithm for traversing a graph.
*
* It discovers all nodes reachable from the starting position by exploring all of the neighbor nodes at the present
* depth prior to moving on to the nodes at the next depth level.
*
* (description adapted from https://en.wikipedia.org/wiki/Breadth-first_search)
* @see https://www.koderdojo.com/blog/breadth-first-search-and-shortest-path-in-csharp-and-net-core
*/
export function breadthFirstSearch(graph, startingNode) {
// visited keeps track of all nodes visited
const visited = new Set()
// queue contains the nodes to be explored in the future
const queue = new Queue()
queue.enqueue(startingNode)
while (!queue.isEmpty()) {
// start with the queue's first node
const node = queue.dequeue()
if (!visited.has(node)) {
// mark the node as visited
visited.add(node)
const neighbors = graph[node]
// put all its neighbors into the queue
for (let i = 0; i < neighbors.length; i++) {
queue.enqueue(neighbors[i])
}
}
}
return visited
}