给定一个链表: 1->2->3->4->5, 和 k = 2.
返回链表 4->5.
通过次数193,790提交次数246,166
来源:力扣(LeetCode)
链接:
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解法一:栈
func getKthFromEnd(_ head: ListNode?, _ k: Int) -> ListNode? {
var node = head
var temp: [ListNode] = []
while let currentNode = node {
temp.insert(currentNode, at: 0)
if temp.count > k {
temp.removeLast()
}
node = currentNode.next
}
return temp.last
}
解法二:差速双指针
func getKthFromEnd(_ head: ListNode?, _ k: Int) -> ListNode? {
var right: ListNode? = head, left: ListNode? = head
// 移动到 第 k 个节点
for _ in 0..<k-1 {
right = right?.next
}
while let _ = right?.next {
right = right?.next
left = left?.next
}
return left
}