|
|
/**
|
|
|
* 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 */
|
|
|
// 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] = []
|
|
|
// 哈希集合，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 */
|
|
|
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))
|
|
|
}
|
|
|
}
|
