feat: add swift implementation to lcof2 problem: No.060 (doocs#3103)

* feat: add swift implementation to lcof2 problem: No.060

* style: format code and docs with prettier

---------

Co-authored-by: Libin YANG <[email protected]>

Author: klever34

lcof2/剑指 Offer II 060. 出现频率最高的 k 个数字/README.md

@@ -198,6 +198,47 @@ impl Solution {
 }
 ```
 
+#### Swift
+
+```swift
+import HeapModule
+
+class Solution {
+    func topKFrequent(_ nums: [Int], _ k: Int) -> [Int] {
+        var frequency: [Int: Int] = [:]
+        for num in nums {
+            frequency[num, default: 0] += 1
+        }
+
+        var freqHeap = Heap<FreqElement>()
+        for (key, value) in frequency {
+            freqHeap.insert(.init(val: key, freq: value))
+            if freqHeap.count > k {
+                freqHeap.removeMin()
+            }
+        }
+        var ans = [Int]()
+        while let element = freqHeap.popMax() {
+            ans.append(element.val)
+        }
+        return ans
+    }
+}
+
+struct FreqElement: Comparable {
+    let val: Int
+    let freq: Int
+
+    static func < (lhs: FreqElement, rhs: FreqElement) -> Bool {
+        lhs.freq < rhs.freq
+    }
+
+    static func == (lhs: FreqElement, rhs: FreqElement) -> Bool {
+        lhs.freq == rhs.freq
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 060. 出现频率最高的 k 个数字/Solution.swift

@@ -0,0 +1,36 @@
+import HeapModule
+
+class Solution {
+    func topKFrequent(_ nums: [Int], _ k: Int) -> [Int] {
+        var frequency: [Int: Int] = [:]
+        for num in nums {
+            frequency[num, default: 0] += 1
+        }
+        
+        var freqHeap = Heap<FreqElement>()
+        for (key, value) in frequency {
+            freqHeap.insert(.init(val: key, freq: value))
+            if freqHeap.count > k {
+                freqHeap.removeMin()
+            }
+        }
+        var ans = [Int]()
+        while let element = freqHeap.popMax() {
+            ans.append(element.val)
+        }
+        return ans
+    }
+}
+
+struct FreqElement: Comparable {
+    let val: Int
+    let freq: Int
+
+    static func < (lhs: FreqElement, rhs: FreqElement) -> Bool {
+        lhs.freq < rhs.freq
+    }
+
+    static func == (lhs: FreqElement, rhs: FreqElement) -> Bool {
+        lhs.freq == rhs.freq
+    }
+}