From 713cf8a15add9929718c62780da54ccc0531c0aa Mon Sep 17 00:00:00 2001
From: Philipp Wallrich <pwallrich@inovex.de>
Date: Thu, 24 Dec 2020 00:16:12 +0100
Subject: [PATCH] Improve LinkedList Array initliasier

---
 Linked List/LinkedList.swift            | 14 ++++++++++++--
 Linked List/Tests/LinkedListTests.swift | 12 ++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/Linked List/LinkedList.swift b/Linked List/LinkedList.swift
index de8a42c93..bd350469c 100755
--- a/Linked List/LinkedList.swift	
+++ b/Linked List/LinkedList.swift	
@@ -270,8 +270,18 @@ extension LinkedList {
 extension LinkedList {
     convenience init(array: Array<T>) {
         self.init()
-        
-        array.forEach { append($0) }
+        guard let first = array.first else {
+            return
+        }
+        var node = Node(value: first)
+        append(node)
+
+        for item in array[1...] {
+            let next = Node(value: item)
+            node.next = next
+            next.previous = node
+            node = next
+        }
     }
 }
 
diff --git a/Linked List/Tests/LinkedListTests.swift b/Linked List/Tests/LinkedListTests.swift
index b16af05ba..6964c547f 100755
--- a/Linked List/Tests/LinkedListTests.swift	
+++ b/Linked List/Tests/LinkedListTests.swift	
@@ -336,4 +336,16 @@ class LinkedListTest: XCTestCase {
         
         XCTAssertTrue(value == 3)
     }
+
+    func testArrayInit() {
+        let testArray = Array(1...10_000)
+
+        let list = LinkedList(array: testArray)
+
+        XCTAssertEqual(list.head?.value, 1)
+        XCTAssertEqual(list.last?.value, 10_000)
+
+        XCTAssertEqual(list.count, 10_000)
+    }
+
 }