42 lines
1.2 KiB
Go
42 lines
1.2 KiB
Go
// File: graph_bfs.go
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// Created Time: 2023-02-18
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// Author: Reanon (793584285@qq.com)
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package chapter_graph
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import (
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. "github.com/krahets/hello-algo/pkg"
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)
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/* Breadth-first traversal */
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// Use adjacency list to represent the graph, to obtain all adjacent vertices of a specified vertex
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func graphBFS(g *graphAdjList, startVet Vertex) []Vertex {
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// Vertex traversal sequence
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res := make([]Vertex, 0)
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// Hash set, used to record visited vertices
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visited := make(map[Vertex]struct{})
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visited[startVet] = struct{}{}
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// Queue used to implement BFS, simulating a queue with a slice
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queue := make([]Vertex, 0)
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queue = append(queue, startVet)
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// Starting from vertex vet, loop until all vertices are visited
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for len(queue) > 0 {
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// Dequeue the vertex at the head of the queue
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vet := queue[0]
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queue = queue[1:]
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// Record visited vertex
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res = append(res, vet)
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// Traverse all adjacent vertices of that vertex
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for _, adjVet := range g.adjList[vet] {
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_, isExist := visited[adjVet]
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// Only enqueue unvisited vertices
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if !isExist {
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queue = append(queue, adjVet)
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visited[adjVet] = struct{}{}
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}
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}
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}
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// Return the vertex traversal sequence
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return res
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}
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