feat: add swift implementation to lcci problem: No.03.02 (doocs#2632)

Author: klever34

lcci/03.02.Min Stack/README.md

@@ -298,6 +298,46 @@ public class MinStack {
  */
 ```
 
+```swift
+class MinStack {
+    private var stk1: [Int]
+    private var stk2: [Int]
+
+    init() {
+        stk1 = []
+        stk2 = [Int.max]
+    }
+
+    func push(_ x: Int) {
+        stk1.append(x)
+
+        stk2.append(min(x, stk2.last!))
+    }
+
+    func pop() {
+        stk1.removeLast()
+        stk2.removeLast()
+    }
+
+    func top() -> Int {
+        return stk1.last!
+    }
+
+    func getMin() -> Int {
+        return stk2.last!
+    }
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * let obj = MinStack();
+ * obj.push(x);
+ * obj.pop();
+ * let param_3 = obj.top();
+ * let param_4 = obj.getMin();
+ */
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/03.02.Min Stack/README_EN.md

@@ -317,6 +317,46 @@ public class MinStack {
  */
 ```
 
+```swift
+class MinStack {
+    private var stk1: [Int]
+    private var stk2: [Int]
+
+    init() {
+        stk1 = []
+        stk2 = [Int.max]
+    }
+
+    func push(_ x: Int) {
+        stk1.append(x)
+
+        stk2.append(min(x, stk2.last!))
+    }
+
+    func pop() {
+        stk1.removeLast()
+        stk2.removeLast()
+    }
+
+    func top() -> Int {
+        return stk1.last!
+    }
+
+    func getMin() -> Int {
+        return stk2.last!
+    }
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * let obj = MinStack();
+ * obj.push(x);
+ * obj.pop();
+ * let param_3 = obj.top();
+ * let param_4 = obj.getMin();
+ */
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/03.02.Min Stack/Solution.swift

@@ -0,0 +1,37 @@
+class MinStack {
+    private var stk1: [Int]
+    private var stk2: [Int]
+
+    init() {
+        stk1 = []
+        stk2 = [Int.max]
+    }
+
+    func push(_ x: Int) {
+        stk1.append(x)
+
+        stk2.append(min(x, stk2.last!))
+    }
+
+    func pop() {
+        stk1.removeLast()
+        stk2.removeLast()
+    }
+
+    func top() -> Int {
+        return stk1.last!
+    }
+
+    func getMin() -> Int {
+        return stk2.last!
+    }
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * let obj = MinStack();
+ * obj.push(x);
+ * obj.pop();
+ * let param_3 = obj.top();
+ * let param_4 = obj.getMin();
+ */