From b211778e6ed8a5fdc758809c3a61dae1f4e34c3a Mon Sep 17 00:00:00 2001
From: Ralph <rdugue1@gmail.com>
Date: Tue, 26 Sep 2023 18:18:19 -0400
Subject: [PATCH 1/2] Stacks and Queues in Kotlin!

---
 .../stacks_and_queues/code/kotlin/Queue.kt    | 33 +++++++++++++++++++
 .../stacks_and_queues/code/kotlin/Stack.kt    | 33 +++++++++++++++++++
 .../stacks_and_queues/stacks_and_queues.md    |  4 +++
 3 files changed, 70 insertions(+)
 create mode 100644 contents/stacks_and_queues/code/kotlin/Queue.kt
 create mode 100644 contents/stacks_and_queues/code/kotlin/Stack.kt

diff --git a/contents/stacks_and_queues/code/kotlin/Queue.kt b/contents/stacks_and_queues/code/kotlin/Queue.kt
new file mode 100644
index 000000000..23f3b64dd
--- /dev/null
+++ b/contents/stacks_and_queues/code/kotlin/Queue.kt
@@ -0,0 +1,33 @@
+class Queue<T> {
+    private val list = mutableListOf<T>()
+
+    fun enqueue(item: T) {
+        list.add(item)
+    }
+
+    fun dequeue(): T? {
+        return if (list.isEmpty()) {
+            null
+        } else list.removeAt(0)
+    }
+
+    fun front(): T? {
+        return if (list.isEmpty()) {
+            null
+        } else list[0]
+    }
+
+    fun size(): Int = return list.size
+}
+
+fun main(args: Array<String>) {
+    val queue = Queue<Int>()
+    queue.enqueue(1)
+    queue.enqueue(2)
+    queue.enqueue(3)
+
+    println("Front: ${queue.front()}")
+    println(queue.dequeue())
+    println("Size: ${queue.size()}")
+    println(queue.dequeue())
+}
\ No newline at end of file
diff --git a/contents/stacks_and_queues/code/kotlin/Stack.kt b/contents/stacks_and_queues/code/kotlin/Stack.kt
new file mode 100644
index 000000000..2833fced4
--- /dev/null
+++ b/contents/stacks_and_queues/code/kotlin/Stack.kt
@@ -0,0 +1,33 @@
+class Stack<T> {
+    private val stack = mutableListOf<T>()
+
+    fun push(item: T) {
+        stack.add(item)
+    }
+
+    fun pop(): T? {
+        return if (stack.isEmpty()) {
+            null
+        } else stack.removeAt(stack.size - 1)
+    }
+
+    fun size(): Int = return stack.size
+
+    fun top(): T? {
+        return if (stack.isEmpty()) {
+            null
+        } else stack[stack.size - 1]
+    }
+}
+
+fun main(args: Array<String>) {
+    val stack = Stack<Int>()
+    stack.push(1)
+    stack.push(2)
+    stack.push(3)
+
+    println("Top: ${stack.top()}")
+    println(stack.pop())
+    println("Size: ${stack.size()}")
+    println(stack.pop())
+}
\ No newline at end of file
diff --git a/contents/stacks_and_queues/stacks_and_queues.md b/contents/stacks_and_queues/stacks_and_queues.md
index e63f72a41..8198b5da1 100644
--- a/contents/stacks_and_queues/stacks_and_queues.md
+++ b/contents/stacks_and_queues/stacks_and_queues.md
@@ -28,6 +28,8 @@ Here is a simple implementation of a stack:
 [import, lang:"rust"](code/rust/Stack.rs)
 {% sample lang="python" %}
 [import, lang:"python"](code/python/stack.py)
+{% sample lang="kotlin" %}
+[import, lang:"kotlin"](code/kotlin/Stack.kt)
 {% endmethod %}
 
 Here is a simple implementation of a queue:
@@ -42,6 +44,8 @@ Here is a simple implementation of a queue:
 [import, lang:"rust" ](code/rust/Queue.rs)
 {% sample lang="python" %}
 [import, lang:"python"](code/python/queue.py)
+{% sample lang="kotlin" %}
+[import, lang:"kotlin"](code/kotlin/Queue.kt)
 {% endmethod %}
 
 ## License

From eca0a4c5365dfadbcec3efd6ae7503036f8e6c80 Mon Sep 17 00:00:00 2001
From: Ralph <rdugue1@gmail.com>
Date: Tue, 26 Sep 2023 19:17:07 -0400
Subject: [PATCH 2/2] Some clean up

---
 contents/stacks_and_queues/code/kotlin/Queue.kt |  2 +-
 contents/stacks_and_queues/code/kotlin/Stack.kt | 14 +++++++-------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/contents/stacks_and_queues/code/kotlin/Queue.kt b/contents/stacks_and_queues/code/kotlin/Queue.kt
index 23f3b64dd..08ff48ffc 100644
--- a/contents/stacks_and_queues/code/kotlin/Queue.kt
+++ b/contents/stacks_and_queues/code/kotlin/Queue.kt
@@ -17,7 +17,7 @@ class Queue<T> {
         } else list[0]
     }
 
-    fun size(): Int = return list.size
+    fun size(): Int = list.size
 }
 
 fun main(args: Array<String>) {
diff --git a/contents/stacks_and_queues/code/kotlin/Stack.kt b/contents/stacks_and_queues/code/kotlin/Stack.kt
index 2833fced4..ecfb75c3b 100644
--- a/contents/stacks_and_queues/code/kotlin/Stack.kt
+++ b/contents/stacks_and_queues/code/kotlin/Stack.kt
@@ -1,22 +1,22 @@
 class Stack<T> {
-    private val stack = mutableListOf<T>()
+    private val list = mutableListOf<T>()
 
     fun push(item: T) {
-        stack.add(item)
+        list.add(item)
     }
 
     fun pop(): T? {
-        return if (stack.isEmpty()) {
+        return if (list.isEmpty()) {
             null
-        } else stack.removeAt(stack.size - 1)
+        } else list.removeAt(list.size - 1)
     }
 
-    fun size(): Int = return stack.size
+    fun size(): Int = list.size
 
     fun top(): T? {
-        return if (stack.isEmpty()) {
+        return if (list.isEmpty()) {
             null
-        } else stack[stack.size - 1]
+        } else list[list.size - 1]
     }
 }