Merge pull request halfrost#156 from brenobaptista/refactored-234

Refactored solution 234

Author: halfrost

leetcode/0234.Palindrome-Linked-List/234. Palindrome Linked List.go

@@ -15,62 +15,22 @@ type ListNode = structures.ListNode
  * }
  */
 
-// 此题和 143 题 Reorder List 思路基本一致
 func isPalindrome234(head *ListNode) bool {
-	if head == nil || head.Next == nil {
-		return true
-	}
-	res := true
-	// 寻找中间结点
-	p1 := head
-	p2 := head
-	for p2.Next != nil && p2.Next.Next != nil {
-		p1 = p1.Next
-		p2 = p2.Next.Next
-	}
+	slice := []int{}
 
-	// 反转链表后半部分  1->2->3->4->5->6 to 1->2->3->6->5->4
-	preMiddle := p1
-	preCurrent := p1.Next
-	for preCurrent.Next != nil {
-		current := preCurrent.Next
-		preCurrent.Next = current.Next
-		current.Next = preMiddle.Next
-		preMiddle.Next = current
+	for head != nil {
+		slice = append(slice, head.Val)
+		head = head.Next
 	}
 
-	// 扫描表，判断是否是回文
-	p1 = head
-	p2 = preMiddle.Next
-	// fmt.Printf("p1 = %v p2 = %v preMiddle = %v head = %v\n", p1.Val, p2.Val, preMiddle.Val, L2ss(head))
-	for p1 != preMiddle {
-		// fmt.Printf("*****p1 = %v p2 = %v preMiddle = %v head = %v\n", p1, p2, preMiddle, L2ss(head))
-		if p1.Val == p2.Val {
-			p1 = p1.Next
-			p2 = p2.Next
-			// fmt.Printf("-------p1 = %v p2 = %v preMiddle = %v head = %v\n", p1, p2, preMiddle, L2ss(head))
-		} else {
-			res = false
-			break
-		}
-	}
-	if p1 == preMiddle {
-		if p2 != nil && p1.Val != p2.Val {
+	for i, j := 0, len(slice)-1; i < j; {
+		if slice[i] != slice[j] {
 			return false
 		}
-	}
-
-	return res
-}
 
-// L2ss define
-func L2ss(head *ListNode) []int {
-	res := []int{}
-
-	for head != nil {
-		res = append(res, head.Val)
-		head = head.Next
+		i++
+		j--
 	}
 
-	return res
+	return true
 }