203. Remove Linked List Elements

Author: TBXark

203. Remove Linked List Elements.md

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+# 203. Remove Linked List Elements
+
+### 2017-03-24
+
+Remove all elements from a linked list of integers that have value **val**.
+
+**Example**
+**\*Given:*** 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, **val** = 6
+**\*Return:*** 1 --> 2 --> 3 --> 4 --> 5
+
+
+
+
+
+# Solution
+
+```swift
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     public var val: Int
+ *     public var next: ListNode?
+ *     public init(_ val: Int) {
+ *         self.val = val
+ *         self.next = nil
+ *     }
+ * }
+ */
+class Solution {
+    func removeElements(_ head: ListNode?, _ val: Int) -> ListNode? {
+        var newHead: ListNode? = nil
+        var newTail: ListNode? = nil
+        var current = head
+        while let c = current {
+            if c.val == val {
+                current = c.next
+            } else {
+               if newTail == nil { 
+                newHead = c
+                newTail = c
+               } else {
+                   newTail?.next = c
+                   newTail = c
+               }
+               current = c.next
+               newTail?.next = nil
+            }
+            
+        }
+        return newHead
+    }
+}
+```
+