Create 0735-asteroid-collision.swift

Author: drxlx

swift/0735-asteroid-collision.swift

@@ -0,0 +1,25 @@
+class Solution {
+    func asteroidCollision(_ asteroids: [Int]) -> [Int] {
+        var stack = [Int]()
+
+        for var a in asteroids {
+            while !stack.isEmpty && a < 0 && stack.last! > 0 {
+                let diff = a + stack.last!
+                if diff < 0 {
+                    stack.popLast()
+                } else if diff > 0 {
+                    a = 0
+                } else {
+                    a = 0
+                    stack.popLast()
+                }
+            }
+
+            if a != 0 {
+                stack.append(a)
+            }
+        }
+
+        return stack
+    }
+}