feat: solve problem 234

easy/234. Palindrome Linked List.go

@@ -0,0 +1,40 @@
+package easy
+
+/**
+ * Definition for singly-linked list.
+ * type ListNode struct {
+ *     Val int
+ *     Next *ListNode
+ * }
+ */
+func isPalindromeLinkedList(head *ListNode) bool {
+	if head.Next == nil {
+		return true
+	}
+	//find middle pointer
+	slow, fast := head, head
+	for fast != nil && fast.Next != nil {
+		slow = slow.Next
+		fast = fast.Next.Next
+	}
+
+	//reverse list from middle element
+	sublist := reverseList(slow)
+
+	//compare two list
+	return compare(sublist, head)
+}
+
+func compare(a, b *ListNode) bool {
+	for a != nil && b != nil {
+		if a.Val != b.Val {
+			return false
+		}
+		a = a.Next
+		b = b.Next
+	}
+	return true
+}
+
+//Time: 0(N/2 + N + N)
+//Space: O(1)