mirror of
https://github.com/krahets/hello-algo.git
synced 2025-11-04 14:18:20 +08:00
870e3e5cb2
* Sync zh and zh-hant versions * Update en/README.md * Add a Q&A for chapter of introduction * Update the callout headers * Sync zh ang zh-hant versions * Bug fixes
65 lines
1.9 KiB
Kotlin
65 lines
1.9 KiB
Kotlin
/**
|
||
* File: graph_bfs.kt
|
||
* Created Time: 2024-01-25
|
||
* Author: curtishd (1023632660@qq.com)
|
||
*/
|
||
|
||
package chapter_graph
|
||
|
||
import utils.Vertex
|
||
import java.util.*
|
||
|
||
/* 廣度優先走訪 */
|
||
// 使用鄰接表來表示圖，以便獲取指定頂點的所有鄰接頂點
|
||
fun graphBFS(graph: GraphAdjList, startVet: Vertex): MutableList<Vertex?> {
|
||
// 頂點走訪序列
|
||
val res = mutableListOf<Vertex?>()
|
||
// 雜湊集合，用於記錄已被訪問過的頂點
|
||
val visited = HashSet<Vertex>()
|
||
visited.add(startVet)
|
||
// 佇列用於實現 BFS
|
||
val que = LinkedList<Vertex>()
|
||
que.offer(startVet)
|
||
// 以頂點 vet 為起點，迴圈直至訪問完所有頂點
|
||
while (!que.isEmpty()) {
|
||
val vet = que.poll() // 佇列首頂點出隊
|
||
res.add(vet) // 記錄訪問頂點
|
||
// 走訪該頂點的所有鄰接頂點
|
||
for (adjVet in graph.adjList[vet]!!) {
|
||
if (visited.contains(adjVet))
|
||
continue // 跳過已被訪問的頂點
|
||
que.offer(adjVet) // 只入列未訪問的頂點
|
||
visited.add(adjVet) // 標記該頂點已被訪問
|
||
}
|
||
}
|
||
// 返回頂點走訪序列
|
||
return res
|
||
}
|
||
|
||
/* Driver Code */
|
||
fun main() {
|
||
/* 初始化無向圖 */
|
||
val v = Vertex.valsToVets(intArrayOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9))
|
||
val edges = arrayOf(
|
||
arrayOf(v[0], v[1]),
|
||
arrayOf(v[0], v[3]),
|
||
arrayOf(v[1], v[2]),
|
||
arrayOf(v[1], v[4]),
|
||
arrayOf(v[2], v[5]),
|
||
arrayOf(v[3], v[4]),
|
||
arrayOf(v[3], v[6]),
|
||
arrayOf(v[4], v[5]),
|
||
arrayOf(v[4], v[7]),
|
||
arrayOf(v[5], v[8]),
|
||
arrayOf(v[6], v[7]),
|
||
arrayOf(v[7], v[8])
|
||
)
|
||
val graph = GraphAdjList(edges)
|
||
println("\n初始化後，圖為")
|
||
graph.print()
|
||
|
||
/* 廣度優先走訪 */
|
||
val res = graphBFS(graph, v[0]!!)
|
||
println("\n廣度優先走訪（BFS）頂點序列為")
|
||
println(Vertex.vetsToVals(res))
|
||
} |