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Merge pull request krahets#218 from nuomi1/feature/linked_list-Swift
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feat: add Swift codes for linked_list article
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@krahets
krahets authored Jan 8, 2023
2 parents e5bc943 + f3e9c2c commit 00e5dfa
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Showing 11 changed files with 244 additions and 73 deletions.
2 changes: 2 additions & 0 deletions codes/swift/Package.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ let package = Package(
.executable(name: "space_complexity", targets: ["space_complexity"]),
.executable(name: "leetcode_two_sum", targets: ["leetcode_two_sum"]),
.executable(name: "array", targets: ["array"]),
.executable(name: "linked_list", targets: ["linked_list"]),
],
targets: [
.target(name: "utils", path: "utils"),
Expand All @@ -18,5 +19,6 @@ let package = Package(
.executableTarget(name: "space_complexity", dependencies: ["utils"], path: "chapter_computational_complexity", sources: ["space_complexity.swift"]),
.executableTarget(name: "leetcode_two_sum", path: "chapter_computational_complexity", sources: ["leetcode_two_sum.swift"]),
.executableTarget(name: "array", path: "chapter_array_and_linkedlist", sources: ["array.swift"]),
.executableTarget(name: "linked_list", dependencies: ["utils"], path: "chapter_array_and_linkedlist", sources: ["linked_list.swift"]),
]
)
91 changes: 91 additions & 0 deletions codes/swift/chapter_array_and_linkedlist/linked_list.swift
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Original file line number Diff line number Diff line change
@@ -0,0 +1,91 @@
/**
* File: linked_list.swift
* Created Time: 2023-01-08
* Author: nuomi1 ([email protected])
*/

import utils

/* 在链表的结点 n0 之后插入结点 P */
func insert(n0: ListNode, P: ListNode) {
let n1 = n0.next
n0.next = P
P.next = n1
}

/* 删除链表的结点 n0 之后的首个结点 */
func remove(n0: ListNode) {
if n0.next == nil {
return
}
// n0 -> P -> n1
let P = n0.next
let n1 = P?.next
n0.next = n1
P?.next = nil
}

/* 访问链表中索引为 index 的结点 */
func access(head: ListNode, index: Int) -> ListNode? {
var head: ListNode? = head
for _ in 0 ..< index {
head = head?.next
if head == nil {
return nil
}
}
return head
}

/* 在链表中查找值为 target 的首个结点 */
func find(head: ListNode, target: Int) -> Int {
var head: ListNode? = head
var index = 0
while head != nil {
if head?.val == target {
return index
}
head = head?.next
index += 1
}
return -1
}

@main
enum LinkedList {
/* Driver Code */
static func main() {
/* 初始化链表 */
// 初始化各个结点
let n0 = ListNode(x: 1)
let n1 = ListNode(x: 3)
let n2 = ListNode(x: 2)
let n3 = ListNode(x: 5)
let n4 = ListNode(x: 4)
// 构建引用指向
n0.next = n1
n1.next = n2
n2.next = n3
n3.next = n4
print("初始化的链表为")
PrintUtil.printLinkedList(head: n0)

/* 插入结点 */
insert(n0: n0, P: ListNode(x: 0))
print("插入结点后的链表为")
PrintUtil.printLinkedList(head: n0)

/* 删除结点 */
remove(n0: n0)
print("删除结点后的链表为")
PrintUtil.printLinkedList(head: n0)

/* 访问结点 */
let node = access(head: n0, index: 3)
print("链表中索引 3 处的结点的值 = \(node!.val)")

/* 查找结点 */
let index = find(head: n0, target: 2)
print("链表中值为 2 的结点的索引 = \(index)")
}
}
16 changes: 8 additions & 8 deletions codes/swift/chapter_computational_complexity/space_complexity.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -6,14 +6,14 @@

import utils

// 函数
/* 函数 */
@discardableResult
func function() -> Int {
// do something
return 0
}

// 常数阶
/* 常数阶 */
func constant(n: Int) {
// 常量、变量、对象占用 O(1) 空间
let a = 0
Expand All @@ -30,7 +30,7 @@ func constant(n: Int) {
}
}

// 线性阶
/* 线性阶 */
func linear(n: Int) {
// 长度为 n 的数组占用 O(n) 空间
let nums = Array(repeating: 0, count: n)
Expand All @@ -40,7 +40,7 @@ func linear(n: Int) {
let map = Dictionary(uniqueKeysWithValues: (0 ..< n).map { ($0, "\($0)") })
}

// 线性阶（递归实现）
/* 线性阶（递归实现） */
func linearRecur(n: Int) {
print("递归 n = \(n)")
if n == 1 {
Expand All @@ -49,13 +49,13 @@ func linearRecur(n: Int) {
linearRecur(n: n - 1)
}

// 平方阶
/* 平方阶 */
func quadratic(n: Int) {
// 二维列表占用 O(n^2) 空间
let numList = Array(repeating: Array(repeating: 0, count: n), count: n)
}

// 平方阶（递归实现）
/* 平方阶（递归实现） */
@discardableResult
func quadraticRecur(n: Int) -> Int {
if n <= 0 {
Expand All @@ -67,7 +67,7 @@ func quadraticRecur(n: Int) -> Int {
return quadraticRecur(n: n - 1)
}

// 指数阶（建立满二叉树）
/* 指数阶（建立满二叉树） */
func buildTree(n: Int) -> TreeNode? {
if n == 0 {
return nil
Expand All @@ -80,7 +80,7 @@ func buildTree(n: Int) -> TreeNode? {

@main
enum SpaceComplexity {
// Driver Code
/* Driver Code */
static func main() {
let n = 5
// 常数阶
Expand Down
47 changes: 24 additions & 23 deletions codes/swift/chapter_computational_complexity/time_complexity.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
* Author: nuomi1 ([email protected])
*/

// 常数阶
/* 常数阶 */
func constant(n: Int) -> Int {
var count = 0
let size = 100_000
Expand All @@ -14,7 +14,7 @@ func constant(n: Int) -> Int {
return count
}

// 线性阶
/* 线性阶 */
func linear(n: Int) -> Int {
var count = 0
for _ in 0 ..< n {
Expand All @@ -23,7 +23,7 @@ func linear(n: Int) -> Int {
return count
}

// 线性阶（遍历数组）
/* 线性阶（遍历数组） */
func arrayTraversal(nums: [Int]) -> Int {
var count = 0
// 循环次数与数组长度成正比
Expand All @@ -33,7 +33,7 @@ func arrayTraversal(nums: [Int]) -> Int {
return count
}

// 平方阶
/* 平方阶 */
func quadratic(n: Int) -> Int {
var count = 0
// 循环次数与数组长度成平方关系
Expand All @@ -45,7 +45,7 @@ func quadratic(n: Int) -> Int {
return count
}

// 平方阶（冒泡排序）
/* 平方阶（冒泡排序） */
func bubbleSort(nums: inout [Int]) -> Int {
var count = 0 // 计数器
// 外循环：待排序元素数量为 n-1, n-2, ..., 1
Expand All @@ -64,7 +64,7 @@ func bubbleSort(nums: inout [Int]) -> Int {
return count
}

// 指数阶（循环实现）
/* 指数阶（循环实现） */
func exponential(n: Int) -> Int {
var count = 0
var base = 1
Expand All @@ -79,15 +79,15 @@ func exponential(n: Int) -> Int {
return count
}

// 指数阶（递归实现）
/* 指数阶（递归实现） */
func expRecur(n: Int) -> Int {
if n == 1 {
return 1
}
return expRecur(n: n - 1) + expRecur(n: n - 1) + 1
}

// 对数阶（循环实现）
/* 对数阶（循环实现） */
func logarithmic(n: Int) -> Int {
var count = 0
var n = n
Expand All @@ -98,15 +98,15 @@ func logarithmic(n: Int) -> Int {
return count
}

// 对数阶（递归实现）
/* 对数阶（递归实现） */
func logRecur(n: Int) -> Int {
if n <= 1 {
return 0
}
return logRecur(n: n / 2) + 1
}

// 线性对数阶
/* 线性对数阶 */
func linearLogRecur(n: Double) -> Int {
if n <= 1 {
return 1
Expand All @@ -118,7 +118,7 @@ func linearLogRecur(n: Double) -> Int {
return count
}

// 阶乘阶（递归实现）
/* 阶乘阶（递归实现） */
func factorialRecur(n: Int) -> Int {
if n == 0 {
return 1
Expand All @@ -133,39 +133,40 @@ func factorialRecur(n: Int) -> Int {

@main
enum TimeComplexity {
/* Driver Code */
static func main() {
// 可以修改 n 运行，体会一下各种复杂度的操作数量变化趋势
let n = 8
print("输入数据大小 n =", n)
print("输入数据大小 n = \(n)")

var count = constant(n: n)
print("常数阶的计算操作数量 =", count)
print("常数阶的计算操作数量 = \(count)")

count = linear(n: n)
print("线性阶的计算操作数量 =", count)
print("线性阶的计算操作数量 = \(count)")
count = arrayTraversal(nums: Array(repeating: 0, count: n))
print("线性阶（遍历数组）的计算操作数量 =", count)
print("线性阶（遍历数组）的计算操作数量 = \(count)")

count = quadratic(n: n)
print("平方阶的计算操作数量 =", count)
print("平方阶的计算操作数量 = \(count)")
var nums = Array(sequence(first: n, next: { $0 > 0 ? $0 - 1 : nil })) // [n,n-1,...,2,1]
count = bubbleSort(nums: &nums)
print("平方阶（冒泡排序）的计算操作数量 =", count)
print("平方阶（冒泡排序）的计算操作数量 = \(count)")

count = exponential(n: n)
print("指数阶（循环实现）的计算操作数量 =", count)
print("指数阶（循环实现）的计算操作数量 = \(count)")
count = expRecur(n: n)
print("指数阶（递归实现）的计算操作数量 =", count)
print("指数阶（递归实现）的计算操作数量 = \(count)")

count = logarithmic(n: n)
print("对数阶（循环实现）的计算操作数量 =", count)
print("对数阶（循环实现）的计算操作数量 = \(count)")
count = logRecur(n: n)
print("对数阶（递归实现）的计算操作数量 =", count)
print("对数阶（递归实现）的计算操作数量 = \(count)")

count = linearLogRecur(n: Double(n))
print("线性对数阶（递归实现）的计算操作数量 =", count)
print("线性对数阶（递归实现）的计算操作数量 = \(count)")

count = factorialRecur(n: n)
print("阶乘阶（递归实现）的计算操作数量 =", count)
print("阶乘阶（递归实现）的计算操作数量 = \(count)")
}
}
10 changes: 5 additions & 5 deletions codes/swift/chapter_computational_complexity/worst_best_time_complexity.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
* Author: nuomi1 ([email protected])
*/

// 生成一个数组，元素为 { 1, 2, ..., n }，顺序被打乱
/* 生成一个数组，元素为 { 1, 2, ..., n }，顺序被打乱 */
func randomNumbers(n: Int) -> [Int] {
// 生成数组 nums = { 1, 2, 3, ..., n }
var nums = Array(1 ... n)
Expand All @@ -13,7 +13,7 @@ func randomNumbers(n: Int) -> [Int] {
return nums
}

// 查找数组 nums 中数字 1 所在索引
/* 查找数组 nums 中数字 1 所在索引 */
func findOne(nums: [Int]) -> Int {
for i in nums.indices {
if nums[i] == 1 {
Expand All @@ -25,14 +25,14 @@ func findOne(nums: [Int]) -> Int {

@main
enum WorstBestTimeComplexity {
// Driver Code
/* Driver Code */
static func main() {
for _ in 0 ..< 10 {
let n = 100
let nums = randomNumbers(n: n)
let index = findOne(nums: nums)
print("数组 [ 1, 2, ..., n ] 被打乱后 =", nums)
print("数字 1 的索引为", index)
print("数组 [ 1, 2, ..., n ] 被打乱后 = \(nums)")
print("数字 1 的索引为 \(index)")
}
}
}
10 changes: 10 additions & 0 deletions codes/swift/utils/PrintUtil.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,16 @@ public enum PrintUtil {
}
}

public static func printLinkedList(head: ListNode) {
var head: ListNode? = head
var list: [String] = []
while head != nil {
list.append("\(head!.val)")
head = head?.next
}
print(list.joined(separator: " -> "))
}

public static func printTree(root: TreeNode?) {
printTree(root: root, prev: nil, isLeft: false)
}
Expand Down
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