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42 lines
1.1 KiB
42 lines
1.1 KiB
// 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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/* 廣度優先走訪 */
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// 使用鄰接表來表示圖，以便獲取指定頂點的所有鄰接頂點
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func graphBFS(g *graphAdjList, startVet Vertex) []Vertex {
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// 頂點走訪序列
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res := make([]Vertex, 0)
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// 雜湊集合，用於記錄已被訪問過的頂點
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visited := make(map[Vertex]struct{})
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visited[startVet] = struct{}{}
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// 佇列用於實現 BFS, 使用切片模擬佇列
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queue := make([]Vertex, 0)
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queue = append(queue, startVet)
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// 以頂點 vet 為起點，迴圈直至訪問完所有頂點
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for len(queue) > 0 {
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// 佇列首頂點出隊
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vet := queue[0]
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queue = queue[1:]
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// 記錄訪問頂點
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res = append(res, vet)
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// 走訪該頂點的所有鄰接頂點
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for _, adjVet := range g.adjList[vet] {
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_, isExist := visited[adjVet]
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// 只入列未訪問的頂點
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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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// 返回頂點走訪序列
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return res
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}
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