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refactor: extract Vertex and use Array<Vertex> (#374)

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* refactor: extract Vertex and use Array<Vertex>

* docs: add chapter to Package.swift

* Update graph_adjacency_list.swift

---------

Co-authored-by: Yudong Jin <krahets@163.com>
This commit is contained in:
nuomi1
2023-02-21 21:35:28 +08:00
committed by GitHub
parent 85be0e286b
commit 04b0fb7455
3 changed files with 74 additions and 35 deletions
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codes/swift/chapter_graph/graph_adjacency_list.swift
+15 -34
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@@ -4,28 +4,13 @@
* Author: nuomi1 (nuomi1@qq.com)
*/
/* 顶点类 */
class Vertex: Hashable {
var val: Int
init(val: Int) {
self.val = val
}
static func == (lhs: Vertex, rhs: Vertex) -> Bool {
lhs.val == rhs.val
}
func hash(into hasher: inout Hasher) {
hasher.combine(val)
}
}
import utils
/* 基于邻接表实现的无向图类 */
class GraphAdjList {
// 邻接表，使用哈希表来代替链表，以提升删除边、删除顶点的效率
// 请注意，adjList 中的元素是 Vertex 对象
private var adjList: [Vertex: Set<Vertex>]
private var adjList: [Vertex: [Vertex]]
/* 构造方法 */
init(edges: [[Vertex]]) {
@@ -49,8 +34,8 @@ class GraphAdjList {
fatalError("参数错误")
}
// 添加边 vet1 - vet2
adjList[vet1]?.insert(vet2)
adjList[vet2]?.insert(vet1)
adjList[vet1]?.append(vet2)
adjList[vet2]?.append(vet1)
}
/* 删除边 */
@@ -59,8 +44,8 @@ class GraphAdjList {
fatalError("参数错误")
}
// 删除边 vet1 - vet2
adjList[vet1]?.remove(vet2)
adjList[vet2]?.remove(vet1)
adjList[vet1]?.removeAll(where: { $0 == vet2 })
adjList[vet2]?.removeAll(where: { $0 == vet1 })
}
/* 添加顶点 */
@@ -81,7 +66,7 @@ class GraphAdjList {
adjList.removeValue(forKey: vet)
// 遍历其它顶点的链表，删除所有包含 vet 的边
for key in adjList.keys {
adjList[key]?.remove(vet)
adjList[key]?.removeAll(where: { $0 == vet })
}
}
@@ -103,25 +88,21 @@ enum GraphAdjacencyList {
/* Driver Code */
static func main() {
/* 初始化无向图 */
let v0 = Vertex(val: 1)
let v1 = Vertex(val: 3)
let v2 = Vertex(val: 2)
let v3 = Vertex(val: 5)
let v4 = Vertex(val: 4)
let edges = [[v0, v1], [v1, v2], [v2, v3], [v0, v3], [v2, v4], [v3, v4]]
let v = Vertex.valsToVets([1, 3, 2, 5, 4])
let edges = [[v[0], v[1]], [v[0], v[3]], [v[1], v[2]], [v[2], v[3]], [v[2], v[4]], [v[3], v[4]]]
let graph = GraphAdjList(edges: edges)
print("\n初始化后，图为")
graph.print()
/* 添加边 */
// 顶点 1, 2 即 v0, v2
graph.addEdge(vet1: v0, vet2: v2)
// 顶点 1, 2 即 v[0], v[2]
graph.addEdge(vet1: v[0], vet2: v[2])
print("\n添加边 1-2 后，图为")
graph.print()
/* 删除边 */
// 顶点 1, 3 即 v0, v1
graph.removeEdge(vet1: v0, vet2: v1)
// 顶点 1, 3 即 v[0], v[1]
graph.removeEdge(vet1: v[0], vet2: v[1])
print("\n删除边 1-3 后，图为")
graph.print()
@@ -132,8 +113,8 @@ enum GraphAdjacencyList {
graph.print()
/* 删除顶点 */
// 顶点 3 即 v1
graph.removeVertex(vet: v1)
// 顶点 3 即 v[1]
graph.removeVertex(vet: v[1])
print("\n删除顶点 3 后，图为")
graph.print()
}