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Use a concise solution for problem 24 swap nodes in pairs

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Signed-off-by: Hanlin Shi <shihanlin9@gmail.com>
This commit is contained in:
Hanlin Shi
2021-05-27 09:48:36 -07:00
parent 11f3e13688
commit 22e9be3663
1 changed files with 4 additions and 25 deletions
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29
leetcode/0024.Swap-Nodes-in-Pairs/24. Swap Nodes in Pairs.go
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@ -16,30 +16,9 @@ type ListNode = structures.ListNode
*/ */
func swapPairs(head *ListNode) *ListNode { func swapPairs(head *ListNode) *ListNode {
if head == nil || head.Next == nil { dummy := &ListNode{Next: head}
return head for pt := dummy; pt != nil && pt.Next != nil && pt.Next.Next != nil; {
pt, pt.Next, pt.Next.Next, pt.Next.Next.Next = pt.Next, pt.Next.Next, pt.Next.Next.Next, pt.Next
} }
s := head.Next return dummy.Next
var behind *ListNode
for head.Next != nil {
headNext := head.Next
if behind != nil && behind.Next != nil {
behind.Next = headNext
}
var next *ListNode
if head.Next.Next != nil {
next = head.Next.Next
}
if head.Next.Next != nil {
head.Next = next
} else {
head.Next = nil
}
headNext.Next = head
behind = head
if head.Next != nil {
head = next
}
}
return s
} }