feat: add swift implementation to lcof2 problem: No.037 (#3047)

Author: klever34

lcof2/剑指 Offer II 037. 小行星碰撞/README.md

@@ -221,6 +221,33 @@ impl Solution {
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    func asteroidCollision(_ asteroids: [Int]) -> [Int] {
+        var stack = [Int]()
+        
+        for asteroid in asteroids {
+            if asteroid > 0 {
+                stack.append(asteroid)
+            } else {
+                while !stack.isEmpty && stack.last! > 0 && stack.last! < -asteroid {
+                    stack.removeLast()
+                }
+                if !stack.isEmpty && stack.last! == -asteroid {
+                    stack.removeLast()
+                } else if stack.isEmpty || stack.last! < 0 {
+                    stack.append(asteroid)
+                }
+            }
+        }
+        
+        return stack
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 037. 小行星碰撞/Solution.swift

@@ -0,0 +1,22 @@
+class Solution {
+    func asteroidCollision(_ asteroids: [Int]) -> [Int] {
+        var stack = [Int]()
+        
+        for asteroid in asteroids {
+            if asteroid > 0 {
+                stack.append(asteroid)
+            } else {
+                while !stack.isEmpty && stack.last! > 0 && stack.last! < -asteroid {
+                    stack.removeLast()
+                }
+                if !stack.isEmpty && stack.last! == -asteroid {
+                    stack.removeLast()
+                } else if stack.isEmpty || stack.last! < 0 {
+                    stack.append(asteroid)
+                }
+            }
+        }
+        
+        return stack
+    }
+}