feat: add swift implementation to lcof2 problem: No.113

Author: klever34

lcof2/剑指 Offer II 113. 课程顺序/README.md

@@ -269,6 +269,46 @@ public class Solution {
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    func findOrder(_ numCourses: Int, _ prerequisites: [[Int]]) -> [Int] {
+        var graph = Array(repeating: [Int](), count: numCourses)
+        var indegree = Array(repeating: 0, count: numCourses)
+        
+        for prereq in prerequisites {
+            let course = prereq[0]
+            let prereqCourse = prereq[1]
+            graph[prereqCourse].append(course)
+            indegree[course] += 1
+        }
+        
+        var queue = [Int]()
+        for i in 0..<numCourses {
+            if indegree[i] == 0 {
+                queue.append(i)
+            }
+        }
+        
+        var order = [Int]()
+        while !queue.isEmpty {
+            let course = queue.removeFirst()
+            order.append(course)
+            
+            for nextCourse in graph[course] {
+                indegree[nextCourse] -= 1
+                if indegree[nextCourse] == 0 {
+                    queue.append(nextCourse)
+                }
+            }
+        }
+        
+        return order.count == numCourses ? order : []
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 113. 课程顺序/Solution.swift

@@ -0,0 +1,35 @@
+class Solution {
+    func findOrder(_ numCourses: Int, _ prerequisites: [[Int]]) -> [Int] {
+        var graph = Array(repeating: [Int](), count: numCourses)
+        var indegree = Array(repeating: 0, count: numCourses)
+        
+        for prereq in prerequisites {
+            let course = prereq[0]
+            let prereqCourse = prereq[1]
+            graph[prereqCourse].append(course)
+            indegree[course] += 1
+        }
+        
+        var queue = [Int]()
+        for i in 0..<numCourses {
+            if indegree[i] == 0 {
+                queue.append(i)
+            }
+        }
+        
+        var order = [Int]()
+        while !queue.isEmpty {
+            let course = queue.removeFirst()
+            order.append(course)
+            
+            for nextCourse in graph[course] {
+                indegree[nextCourse] -= 1
+                if indegree[nextCourse] == 0 {
+                    queue.append(nextCourse)
+                }
+            }
+        }
+        
+        return order.count == numCourses ? order : []
+    }
+}