19. Remove Nth Node From End of List

Given a linked list, remove the nth node from the end of list and return its head.

For example,

Given linked list: 1->2->3->4->5, and n = 2.

After removing the second node from the end, the linked list becomes 1->2->3->5.

Note:

Given n will always be valid.

Try to do this in one pass.

一次遍历删除倒数第n个节点

package leet

//Definition for singly-linked list.
type ListNode struct {
Val  int
Next *ListNode
}

func removeNthFromEnd(head *ListNode, n int) *ListNode {
p1 := head
p2 := head
for n > 0 {
p1 = p1.Next
n--
}
if p1 == nil {
return head.Next
}
for p1.Next != nil {
p1 = p1.Next
p2 = p2.Next
}
p2.Next = p2.Next.Next
return head
}