Fixed insert method and some related files.

Author: yossan

Diff for: Linked List/LinkedList.playground/Contents.swift

@@ -145,17 +145,17 @@ public final class LinkedList<T> {
   /// - Parameters:
   ///   - node: The node containing the value to be inserted
   ///   - index: Integer value of the index to be inserted at
-  public func insert(_ node: Node, atIndex index: Int) {
-    let newNode = node
+  public func insert(_ newNode: Node, atIndex index: Int) {
     if index == 0 {
       newNode.next = head
       head?.previous = newNode
       head = newNode
     } else {
-      let prev = self.node(atIndex: index-1)
+      let prev = node(atIndex: index-1)
+      let next = prev.next
       newNode.previous = prev
-      newNode.next = prev.next
-      prev.next?.previous = newNode
+      newNode.next = next
+      next?.previous = newNode
       prev.next = newNode
     }
   }
@@ -169,18 +169,17 @@ public final class LinkedList<T> {
     if list.isEmpty { return }
 
     if index == 0 {
-      let temp = head
+      list.last?.next = head
       head = list.head
-      list.last?.next = temp
     } else {
-      let prev = self.node(atIndex: index-1)
-      let temp = prev.next
+      let prev = node(atIndex: index-1)
+      let next = prev.next
 
       prev.next = list.head
       list.head?.previous = prev
 
-      list.last?.next = temp
-      temp?.previous = list.last?.next
+      list.last?.next = next
+      next?.previous = list.last?.next
     }
   }
 

Diff for: Linked List/LinkedList.swift

@@ -100,17 +100,17 @@ public final class LinkedList<T> {
         self.insert(newNode, atIndex: index)
     }
 
-    public func insert(_ node: Node, atIndex index: Int) {
-        let newNode = node
+    public func insert(_ newNode: Node, atIndex index: Int) {
         if index == 0 {
             newNode.next = head
             head?.previous = newNode
             head = newNode
         } else {
-            let prev = self.node(atIndex: index-1)
+            let prev = node(atIndex: index-1)
+            let next = prev.next
             newNode.previous = prev
-            newNode.next = prev.next
-            prev.next?.previous = newNode
+            newNode.next = next
+            next?.previous = newNode
             prev.next = newNode
         }
     }
@@ -119,18 +119,17 @@ public final class LinkedList<T> {
         if list.isEmpty { return }
 
         if index == 0 {
-            let temp = head
+            list.last?.next = head
             head = list.head
-            list.last?.next = temp
         } else {
             let prev = self.node(atIndex: index-1)
-            let temp = prev.next
+            let next = prev.next
 
             prev.next = list.head
             list.head?.previous = prev
 
-            list.last?.next = temp
-            temp?.previous = list.last?.next
+            list.last?.next = next
+            next?.previous = list.last?.next
         }
     }
 

Diff for: Linked List/README.markdown

@@ -330,18 +330,18 @@ Finally, replace the head with the new node.
              |    C    |    |    A    |     |    B    |
      nil <---|         |<---|         |<----|         |<----//------
              +---------+    +---------+     +---------+ 
-                 [0]            [1]
+                 [0]            [1]             [2]
 
 
 However, when the given index is greater than 0, it is necessary to get the node previous and next index and insert between them.
 You can also obtain the previous and next node using node(atIndex:) as follows:
 
              +---------+         +---------+     +---------+    
     head --->|         |---//--->|         |---->|         |----
-             |    0    |         |    A    |     |    B    |    
+             |         |         |    A    |     |    B    |    
      nil <---|         |---//<---|         |<----|         |<---
              +---------+         +---------+     +---------+    
-                                  [index-1]        [index]      
+                 [0]              [index-1]        [index]      
                                       ^               ^ 
                                       |               | 
                                      prev            next
@@ -356,10 +356,10 @@ Now insert new node between the prev and the next.
 
              +---------+         +---------+     +---------+     +---------+
     head --->|         |---//--->|         |---->|         |---->|         |
-             |    0    |         |    A    |     |    C    |     |    B    |
+             |         |         |    A    |     |    C    |     |    B    |
      nil <---|         |---//<---|         |<----|         |<----|         |
              +---------+         +---------+     +---------+     +---------+
-                                  [index-1]        [index]        [index+1]
+                 [0]              [index-1]        [index]        [index+1]
                                       ^               ^               ^
                                       |               |               |
                                      prev            new             next