735. Asteroid Collision

Author: a-khakimov

leetcode-scala/src/main/scala/LeetCode75/Stack/735. Asteroid Collision.sc

@@ -0,0 +1,30 @@
+object Solution {
+  def asteroidCollision(asteroids: Array[Int]): Array[Int] = {
+    val stack = scala.collection.mutable.Stack.empty[Int]
+    for (asteroid <- asteroids) {
+      if (asteroid > 0) {
+        stack.push(asteroid)
+      } else {
+        while (stack.nonEmpty && stack.top > 0 && stack.top < -asteroid) {
+          stack.pop()
+        }
+        if (stack.nonEmpty && stack.top == -asteroid) {
+          println(s"top=${stack.top} asteroid=$asteroid")
+          stack.pop()
+        } else if (stack.isEmpty || stack.top < 0) {
+          stack.push(asteroid)
+        }
+      }
+    }
+    stack.toArray.reverse
+  }
+}
+
+Solution.asteroidCollision(Array(5,10,-5)) // [5,10]
+Solution.asteroidCollision(Array(8,-8)) // []
+Solution.asteroidCollision(Array(10,2,-5)) // [10]
+Solution.asteroidCollision(Array(-2,-1,1,2)) // [-2,-1,1,2]
+Solution.asteroidCollision(Array(-3,-2,-1,1,2,3)) // [-3,-2,-1,1,2,3]
+Solution.asteroidCollision(Array(3,2,1,-1,-2,-3)) // []
+Solution.asteroidCollision(Array(-2,2,-1,-2)) // [-2]
+