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feat: add Swift codes for graph_traversal article (#378)

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* feat: add Swift codes for graph_traversal article

* refactor: rename parameters

* Update graph_dfs.swift

---------

Co-authored-by: Yudong Jin <krahets@163.com>
pull/380/head
nuomi1 2 years ago committed by GitHub
parent f2d2cca5f1
commit c6c4c9d997
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GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 136 additions and 13 deletions
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6
codes/swift/Package.swift
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@ -37,6 +37,8 @@ let package = Package(
// chapter_graph
.executable(name: "graph_adjacency_matrix", targets: ["graph_adjacency_matrix"]),
.executable(name: "graph_adjacency_list", targets: ["graph_adjacency_list"]),
.executable(name: "graph_bfs", targets: ["graph_bfs"]),
.executable(name: "graph_dfs", targets: ["graph_dfs"]),
// chapter_searching
.executable(name: "linear_search", targets: ["linear_search"]),
.executable(name: "binary_search", targets: ["binary_search"]),
@ -49,7 +51,9 @@ let package = Package(
.executable(name: "radix_sort", targets: ["radix_sort"]),
],
targets: [
// helper
.target(name: "utils", path: "utils"),
.target(name: "graph_adjacency_list_target", dependencies: ["utils"], path: "chapter_graph", sources: ["graph_adjacency_list_target.swift"], swiftSettings: [.define("TARGET")]),
// chapter_computational_complexity
.executableTarget(name: "time_complexity", path: "chapter_computational_complexity", sources: ["time_complexity.swift"]),
.executableTarget(name: "worst_best_time_complexity", path: "chapter_computational_complexity", sources: ["worst_best_time_complexity.swift"]),
@ -82,6 +86,8 @@ let package = Package(
// chapter_graph
.executableTarget(name: "graph_adjacency_matrix", dependencies: ["utils"], path: "chapter_graph", sources: ["graph_adjacency_matrix.swift"]),
.executableTarget(name: "graph_adjacency_list", dependencies: ["utils"], path: "chapter_graph", sources: ["graph_adjacency_list.swift"]),
.executableTarget(name: "graph_bfs", dependencies: ["utils", "graph_adjacency_list_target"], path: "chapter_graph", sources: ["graph_bfs.swift"]),
.executableTarget(name: "graph_dfs", dependencies: ["utils", "graph_adjacency_list_target"], path: "chapter_graph", sources: ["graph_dfs.swift"]),
// chapter_searching
.executableTarget(name: "linear_search", dependencies: ["utils"], path: "chapter_searching", sources: ["linear_search.swift"]),
.executableTarget(name: "binary_search", path: "chapter_searching", sources: ["binary_search.swift"]),

24
codes/swift/chapter_graph/graph_adjacency_list.swift
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@ -7,13 +7,13 @@
import utils
/* 基于邻接表实现的无向图类 */
class GraphAdjList {
public 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: [Vertex]]
public private(set) var adjList: [Vertex: [Vertex]]
/* 构造方法 */
init(edges: [[Vertex]]) {
public init(edges: [[Vertex]]) {
adjList = [:]
// 添加所有顶点和边
for edge in edges {
@ -24,12 +24,12 @@ class GraphAdjList {
}
/* 获取顶点数量 */
func size() -> Int {
public func size() -> Int {
adjList.count
}
/* 添加边 */
func addEdge(vet1: Vertex, vet2: Vertex) {
public func addEdge(vet1: Vertex, vet2: Vertex) {
if adjList[vet1] == nil || adjList[vet2] == nil || vet1 == vet2 {
fatalError("参数错误")
}
@ -39,7 +39,7 @@ class GraphAdjList {
}
/* 删除边 */
func removeEdge(vet1: Vertex, vet2: Vertex) {
public func removeEdge(vet1: Vertex, vet2: Vertex) {
if adjList[vet1] == nil || adjList[vet2] == nil || vet1 == vet2 {
fatalError("参数错误")
}
@ -49,7 +49,7 @@ class GraphAdjList {
}
/* 添加顶点 */
func addVertex(vet: Vertex) {
public func addVertex(vet: Vertex) {
if adjList[vet] != nil {
return
}
@ -58,7 +58,7 @@ class GraphAdjList {
}
/* 删除顶点 */
func removeVertex(vet: Vertex) {
public func removeVertex(vet: Vertex) {
if adjList[vet] == nil {
fatalError("参数错误")
}
@ -71,7 +71,7 @@ class GraphAdjList {
}
/* 打印邻接表 */
func print() {
public func print() {
Swift.print("邻接表 =")
for entry in adjList {
var tmp: [Int] = []
@ -83,12 +83,14 @@ class GraphAdjList {
}
}
#if !TARGET
@main
enum GraphAdjacencyList {
/* Driver Code */
static func main() {
/* 初始化无向图 */
let v = Vertex.valsToVets([1, 3, 2, 5, 4])
let v = Vertex.valsToVets(vals: [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")
@ -119,3 +121,5 @@ enum GraphAdjacencyList {
graph.print()
}
}
#endif

1
codes/swift/chapter_graph/graph_adjacency_list_target.swift
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@ -0,0 +1 @@
graph_adjacency_list.swift

56
codes/swift/chapter_graph/graph_bfs.swift
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@ -0,0 +1,56 @@
/**
* File: graph_bfs.swift
* Created Time: 2023-02-21
* Author: nuomi1 (nuomi1@qq.com)
*/
import graph_adjacency_list_target
import utils
/* 广度优先遍历 BFS */
// 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 graphBFS(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> = [startVet]
// 队列用于实现 BFS
var que: [Vertex] = [startVet]
// 以顶点 vet 为起点，循环直至访问完所有顶点
while !que.isEmpty {
let vet = que.removeFirst() // 队首顶点出队
res.append(vet) // 记录访问顶点
// 遍历该顶点的所有邻接顶点
for adjVet in graph.adjList[vet] ?? [] {
if visited.contains(adjVet) {
continue // 跳过已被访问过的顶点
}
que.append(adjVet) // 只入队未访问的顶点
visited.insert(adjVet) // 标记该顶点已被访问
}
}
// 返回顶点遍历序列
return res
}
@main
enum GraphBFS {
/* Driver Code */
static func main() {
/* 初始化无向图 */
let v = Vertex.valsToVets(vals: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
let edges = [
[v[0], v[1]], [v[0], v[3]], [v[1], v[2]], [v[1], v[4]],
[v[2], v[5]], [v[3], v[4]], [v[3], v[6]], [v[4], v[5]],
[v[4], v[7]], [v[5], v[8]], [v[6], v[7]], [v[7], v[8]],
]
let graph = GraphAdjList(edges: edges)
print("\n初始化后，图为")
graph.print()
/* 广度优先遍历 BFS */
let res = graphBFS(graph: graph, startVet: v[0])
print("\n广度优先遍历（BFS）顶点序列为")
print(Vertex.vetsToVals(vets: res))
}
}

54
codes/swift/chapter_graph/graph_dfs.swift
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@ -0,0 +1,54 @@
/**
* 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 // 跳过已被访问过的顶点
}
// 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))
}
}

4
codes/swift/utils/Vertex.swift
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@ -21,7 +21,7 @@ public class Vertex: Hashable {
}
/* 输入值列表 vals ，返回顶点列表 vets */
public static func valsToVets(_ vals: [Int]) -> [Vertex] {
public static func valsToVets(vals: [Int]) -> [Vertex] {
var vets: [Vertex] = []
for val in vals {
vets.append(Vertex(val: val))
@ -30,7 +30,7 @@ public class Vertex: Hashable {
}
/* 输入顶点列表 vets ，返回值列表 vals */
public static func vetsToVals(_ vets: [Vertex]) -> [Int] {
public static func vetsToVals(vets: [Vertex]) -> [Int] {
var vals: [Int] = []
for vet in vets {
vals.append(vet.val)

4
docs/chapter_graph/graph_traversal.md
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@ -79,7 +79,7 @@ BFS 常借助「队列」来实现。队列具有“先入先出”的性质，
=== "Swift"
```swift title="graph_bfs.swift"
[class]{}-[func]{graphBFS}
```
=== "Zig"
@ -196,7 +196,9 @@ BFS 常借助「队列」来实现。队列具有“先入先出”的性质，
=== "Swift"
```swift title="graph_dfs.swift"
[class]{}-[func]{dfs}
[class]{}-[func]{graphDFS}
```
=== "Zig"

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