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hello-algo/codes/swift/chapter_graph/graph_dfs.swift
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Yudong Jin e720aa2d24 feat: Revised the book (#978)
* Sync recent changes to the revised Word.

* Revised the preface chapter

* Revised the introduction chapter

* Revised the computation complexity chapter

* Revised the chapter data structure

* Revised the chapter array and linked list

* Revised the chapter stack and queue

* Revised the chapter hashing

* Revised the chapter tree

* Revised the chapter heap

* Revised the chapter graph

* Revised the chapter searching

* Reivised the sorting chapter

* Revised the divide and conquer chapter

* Revised the chapter backtacking

* Revised the DP chapter

* Revised the greedy chapter

* Revised the appendix chapter

* Revised the preface chapter doubly

* Revised the figures
2023-12-02 06:21:34 +08:00

55 lines
1.7 KiB
Swift

/**
* File: graph_dfs.swift
* Created Time: 2023-02-21
* Author: nuomi1 (nuomi1@qq.com)
*/
import graph_adjacency_list_target
import utils
/* 深度优先遍历 DFS 辅助函数 */
func dfs(graph: GraphAdjList, visited: inout Set<Vertex>, res: inout [Vertex], vet: Vertex) {
res.append(vet) // 记录访问顶点
visited.insert(vet) // 标记该顶点已被访问
// 遍历该顶点的所有邻接顶点
for adjVet in graph.adjList[vet] ?? [] {
if visited.contains(adjVet) {
continue // 跳过已被访问的顶点
}
// 递归访问邻接顶点
dfs(graph: graph, visited: &visited, res: &res, vet: adjVet)
}
}
/* 深度优先遍历 DFS */
// 使用邻接表来表示图,以便获取指定顶点的所有邻接顶点
func graphDFS(graph: GraphAdjList, startVet: Vertex) -> [Vertex] {
// 顶点遍历序列
var res: [Vertex] = []
// 哈希表,用于记录已被访问过的顶点
var visited: Set<Vertex> = []
dfs(graph: graph, visited: &visited, res: &res, vet: startVet)
return res
}
@main
enum GraphDFS {
/* Driver Code */
static func main() {
/* 初始化无向图 */
let v = Vertex.valsToVets(vals: [0, 1, 2, 3, 4, 5, 6])
let edges = [
[v[0], v[1]], [v[0], v[3]], [v[1], v[2]],
[v[2], v[5]], [v[4], v[5]], [v[5], v[6]],
]
let graph = GraphAdjList(edges: edges)
print("\n初始化后,图为")
graph.print()
/* 深度优先遍历 DFS */
let res = graphDFS(graph: graph, startVet: v[0])
print("\n深度优先遍历(DFS)顶点序列为")
print(Vertex.vetsToVals(vets: res))
}
}