feat: add swift implementation to lcof problem: No.59.2 (#2951)

Author: klever34

lcof/面试题59 - II. 队列的最大值/README.md

@@ -422,6 +422,49 @@ public class MaxQueue {
  */
 ```
 
+#### Swift
+
+```swift
+class MaxQueue {
+    private var q1: [Int] = []
+    private var q2: [Int] = []
+    
+    init() {
+    }
+    
+    func max_value() -> Int {
+        return q2.isEmpty ? -1 : q2.first!
+    }
+    
+    func push_back(_ value: Int) {
+        q1.append(value)
+        while !q2.isEmpty && q2.last! < value {
+            q2.removeLast()
+        }
+        q2.append(value)
+    }
+    
+    func pop_front() -> Int {
+        if q1.isEmpty {
+            return -1
+        }
+        let ans = q1.removeFirst()
+        if q2.first == ans {
+            q2.removeFirst()
+        }
+        return ans
+    }
+}
+
+/**
+ * Your MaxQueue object will be instantiated and called as such:
+ * let obj = MaxQueue();
+ * let param_1 = obj.max_value();
+ * obj.push_back(value);
+ * let param_3 = obj.pop_front();
+ */
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof/面试题59 - II. 队列的最大值/Solution.swift

@@ -0,0 +1,30 @@
+class MaxQueue {
+    private var q1: [Int] = []
+    private var q2: [Int] = []
+    
+    init() {
+    }
+    
+    func max_value() -> Int {
+        return q2.isEmpty ? -1 : q2.first!
+    }
+    
+    func push_back(_ value: Int) {
+        q1.append(value)
+        while !q2.isEmpty && q2.last! < value {
+            q2.removeLast()
+        }
+        q2.append(value)
+    }
+    
+    func pop_front() -> Int {
+        if q1.isEmpty {
+            return -1
+        }
+        let ans = q1.removeFirst()
+        if q2.first == ans {
+            q2.removeFirst()
+        }
+        return ans
+    }
+}