Merge pull request #140 from hanlins/24/one-liner

Use a concise solution for problem 24 swap nodes in pairs
This commit is contained in:
halfrost
2021-05-28 13:29:41 +08:00
committed by GitHub

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@@ -16,30 +16,9 @@ type ListNode = structures.ListNode
*/
func swapPairs(head *ListNode) *ListNode {
if head == nil || head.Next == nil {
return head
dummy := &ListNode{Next: 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
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
return dummy.Next
}