leetcode

commit 5d7859c2eaf3acda006d2625fa521f4e465a4d7f
parent 2a0bc686a8f5e5584637050f175832a7215d8c5f
Author: AndrewLockVI <andrewlaack1@gmail.com>
Date:   Sat, 22 Apr 2023 12:28:46 -0500

Palindrome linked list checker

Diffstat:
A
palindrome-linked-list/palindrome-linked-list.dart
 | 
45
+++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 45 insertions(+), 0 deletions(-)
diff --git a/palindrome-linked-list/palindrome-linked-list.dart b/palindrome-linked-list/palindrome-linked-list.dart
@@ -0,0 +1,45 @@
+//Find if the values contained within a linked list are a palindrome.
+//To do this I iterated through the list putting all of the values into
+//an array and then at the end I checked to make sure the second half of the 
+//array was the same as the first half.
+//The time complexity of this is O(n) where n is the number of nodes in the list.
+
+//Runtime: 339ms Beats: 68.25%
+//Memory: 208.8MB Beats: 17.46%
+
+
+/**
+ * Definition for singly-linked list.
+ * class ListNode {
+ *   int val;
+ *   ListNode? next;
+ *   ListNode([this.val = 0, this.next]);
+ * }
+ */
+class Solution {
+  bool isPalindrome(ListNode? head) {
+      if(head?.next == null){
+          return true;
+      }
+
+      List<int> nums = [];
+      while(true){
+          if(head == null){
+              break;
+          }
+          nums.add(head?.val ?? 0);
+          head = head?.next;
+      }
+      
+      for(int i = 0 ; i < (nums.length / 2).ceil() ; ++i){
+          if(nums[i] == nums[nums.length - 1 - i]){
+              continue;
+          }
+          else{
+              return false;
+          }
+      }
+
+      return true;
+  }
+}